                         UNPUBLISHED

UNITED STATES COURT OF APPEALS
                FOR THE FOURTH CIRCUIT


DENNIS S. KOZLOWSKI,                   
                Plaintiff-Appellant,
                 v.
HAMPTON SCHOOL BOARD,
              Defendant-Appellee,               No. 02-1485
                and
BETHEL HIGH SCHOOL; CITY OF
HAMPTON,
                       Defendants.
                                       
           Appeal from the United States District Court
      for the Eastern District of Virginia, at Newport News.
              James E. Bradberry, Magistrate Judge.
                           (CA-01-37-4)

                       Argued: May 8, 2003

                      Decided: October 3, 2003

       Before LUTTIG and MICHAEL, Circuit Judges, and
    Joseph R. GOODWIN, United States District Judge for the
     Southern District of West Virginia, sitting by designation.



Vacated and remanded by unpublished opinion. Judge Goodwin
wrote the opinion, in which Judge Luttig and Judge Michael joined.


                            COUNSEL

ARGUED: David Michael Pearline, LAW OFFICE OF DAVID
PEARLINE, Virginia Beach, Virginia, for Appellant. Cynthia Eppes
2               KOZLOWSKI v. HAMPTON SCHOOL BOARD
Hudson, Deputy City Attorney, HAMPTON CITY ATTORNEY’S
OFFICE, Hampton, Virginia, for Appellee.



Unpublished opinions are not binding precedent in this circuit. See
Local Rule 36(c).


                              OPINION

GOODWIN, District Judge:

   Dennis Kozlowski, the long-time head football coach at Bethel
High School in Hampton, Virginia, brought suit against the Hampton
City School Board under the Age Discrimination in Employment Act
of 1967 (ADEA), 29 U.S.C. § 623 et seq. Kozlowski claimed that the
Board, acting through its agent, Principal William Pearson, failed to
renew his coaching contract because of his age. The case went to trial,
and the jury returned a verdict for the defendant School Board. On
appeal, Kozlowski raises various challenges to the court’s jury
instructions, two challenges to the court’s evidentiary rulings, and an
additional challenge to the court’s failure to sequester Pearson from
the trial. After review, we conclude that the district court erred by
excluding evidence of prior similar acts of age discrimination by
Pearson, by admitting evidence of Kozlowski’s prior DUI arrests, and
by refusing to sequester Pearson, a main defense fact witness. The
court also erred by failing to instruct the jury that it could infer dis-
crimination if it did not believe the proffered reasons for the non-
renewal. Any one of these errors standing alone may have been harm-
less; considered collectively, however, the errors were substantially
prejudicial to Kozlowski’s case. Accordingly, we vacate the judgment
of the district court and remand for a new trial.

                                   I.

   The plaintiff, Dennis Kozlowski, worked at Bethel High School
from 1968 to 2000. At various times during his tenure at Bethel,
Kozlowski served as an English instructor, track coach, football
                KOZLOWSKI v. HAMPTON SCHOOL BOARD                     3
coach, interim basketball coach, and athletic director. Starting in
1974, Kozlowski served as the head football coach. During his foot-
ball coaching career, his teams won three state championships and a
number of other honors. Kozlowski was employed as football coach
at Bethel by the Hampton City School Board under one-year contracts
that were annually renewed by the Board. While the Board took the
formal action to renew contracts, the Board had delegated its author-
ity over contract renewal to the local school administrators, here the
Bethel High School principal, and accepted as a matter of course the
principal’s recommendations regarding renewal.

   In the fall of 1993, William Pearson became the new principal at
Bethel High School. Pearson had previously served as a teacher and
assistant principal at various schools in the area, and during these
years had been actively involved in the schools’ athletic programs,
coaching a number of sports including football. He testified that he
was "very involved in every athletic endeavor" at Bethel from the day
he was hired. Pearson paid very close attention to the football pro-
gram, attending almost every game and scrimmage and also attending
practice once or twice a week for the whole season.

   In December of 1998, Pearson recommended another candidate,
Tracy Parker, to the Board for head football coach. The Board fol-
lowed Pearson’s recommendation, and Kozlowski’s coaching contract
was not renewed for the following year. Kozlowski’s teaching and
athletic director contracts were renewed, however, and he held those
positions until his retirement the following year. At the time of the
non-renewal, Pearson and Kozlowski were both fifty-four years old.
Parker, Kozlowski’s replacement, was under forty years old.

   Pearson met with Kozlowski on December 4, 1998, to discuss his
plans to replace Kozlowski as head coach. Both sides agree that a
number of reasons for non-renewal were discussed at this meeting,
including Kozlowski’s use of an ineligible player, his failure to attend
a coaches’ All-District meeting, and Pearson’s dissatisfaction with the
overall direction of the football program. According to Kozlowski,
Pearson also told him that "I want a younger coach. . . . I need new
blood in it. I want people who can communicate with the kids better."
Pearson denies saying anything to Kozlowski about his age. On
December 10, Pearson prepared a memo to Kozlowski informing him
4                KOZLOWSKI v. HAMPTON SCHOOL BOARD
of Pearson’s final decision not to renew his contract. In this memo,
Pearson provided the following reasons for non-renewal: "Over the
past two years, I have observed many instances of poor handling of
football players, player distractions, and overall team dissension and
dysfunction which probably contributed to the level of play on the
field . . . ." He also mentioned the ineligible player and missing the
district coaches’ meeting. The letter does not mention Kozlowski’s
age.

   Kozlowski responded by writing a letter dated January 5, 1999, in
which he tried to address the issues raised by Pearson. Pearson denies
receiving this letter. In January of 1999, Kozlowski wrote to the
superintendent of the Hampton City Schools about Pearson’s recom-
mendation. The Board then met with Kozlowski in a closed session
in February of 1999, where Kozlowski was represented by counsel
and was given the opportunity to present his case. Pearson wrote a let-
ter to the School Board chairman in March of 1999 detailing the rea-
sons for the non-renewal recommendation. The Board ultimately
decided to accept Pearson’s recommendation, as was their usual prac-
tice.

   Kozlowski filed a charge with the Equal Employment Opportunity
Commission (EEOC) alleging age discrimination, and the EEOC
issued Kozlowski a right-to-sue letter. Kozlowski then brought the
current age discrimination suit under the ADEA. The parties con-
sented to try the case before Magistrate Judge James E. Bradberry,
and the case went to trial.1 The jury returned a verdict for the defen-
dant School Board. Kozlowski now appeals.

   At trial, plaintiff’s counsel proffered various jury instructions,
some of which were accepted, with modifications, by the district
court. In addition to a general age discrimination instruction, the
plaintiff proffered a pretext instruction modeled after the burden-
shifting scheme established in McDonnell Douglas Corp. v. Green,
411 U.S. 792 (1973), and a mixed-motive instruction modeled after
the standard established in Price Waterhouse v. Hopkins, 490 U.S.
228 (1989). On appeal, the plaintiff objects to various aspects of the
    1
   For the sake of simplicity, we will refer to the magistrate judge as the
district court.
                KOZLOWSKI v. HAMPTON SCHOOL BOARD                       5
final jury instructions. Specifically, the plaintiff appeals (1) the
court’s failure to provide one of the requested mixed-motive instruc-
tions; (2) the court’s insertion of "because of age" into the McDonnell
Douglas prima facie case; (3) the court’s refusal to instruct the jury
that it could infer age discrimination from the falsity of the defen-
dant’s proffered reasons; and (4) the court’s insertion of the term
"solely" into the phrase "because of age." The plaintiff also appeals
two evidentiary rulings. First, the plaintiff appeals the district court’s
exclusion of evidence proffered by the plaintiff of prior similar
alleged acts of age discrimination. Second, the plaintiff appeals the
district court’s admission of evidence related to Kozlowski’s past
arrests for driving under the influence of alcohol. Finally, the plaintiff
appeals the district court’s refusal to sequester Pearson, a primary
defense witness, from the trial proceedings. We first address the
plaintiff’s various challenges to the jury instructions, and then take up
his evidentiary and sequestration claims. After we address each
ground for appeal separately, we will address whether the errors taken
as a whole warrant a new trial.

                                   II.

   As noted above, the plaintiff raises four challenges to the court’s
jury instructions. At trial the plaintiff objected to the court’s rulings
on the first three of these issues, but failed to object to the fourth
ground for appeal, the court’s use of the term "solely." We will first
discuss the three non-forfeited instructional issues and then turn to the
forfeited error.

                                   A.

   We review a district court’s refusal to give a requested instruction
for abuse of discretion. United States v. Abbas, 74 F.3d 506, 513 (4th
Cir. 1996). As for challenges to the content of an instruction, the test
"is simply the practical one of whether the instructions construed as
a whole, and in light of the whole record, adequately informed the
jury of the controlling legal principles without misleading or confus-
ing the jury to the prejudice of the objecting party." Spell v. McDan-
iel, 824 F.2d 1380, 1395 (4th Cir. 1987). A court has "considerable
discretion in choosing the specific wording of instructions." United
States v. Piche, 981 F.2d 706, 712 (4th Cir. 1992). "Even if instruc-
6               KOZLOWSKI v. HAMPTON SCHOOL BOARD
tions are flawed, there can be no reversal unless the error seriously
prejudiced the challenging party’s case." S. Atl. Ltd. P’ship of Tenn.
v. Riese, 284 F.3d 518, 530 (4th Cir. 2002).

   The plaintiff’s non-forfeited challenges to the jury instructions are:
(1) the court’s refusal to give a requested mixed-motive instruction;
(2) the court’s modification of the prima facie case instruction to
include "because of age;" and (3) the court’s refusal to instruct the
jury that it could infer discrimination from its disbelief of the defen-
dant’s proffered legitimate reasons.

   In order to place these objections in context, we must first set out
briefly the legal frameworks governing age discrimination cases.
There are two methods by which a plaintiff may prevail in an age dis-
crimination case. Under the first method, the mixed-motive frame-
work, the plaintiff must prove that age played a substantial motivating
role in the defendant’s decision. See Fuller v. Phipps, 67 F.3d 1137,
1142 (4th Cir. 1995) (citing Price Waterhouse v. Hopkins, 490 U.S.
228, 277 (1989) (O’Connor, J., concurring)), abrogated on other
grounds, Desert Palace, Inc. v. Costa, 539 U.S. ___, 123 S.Ct. 2148
(2003). If the plaintiff makes this showing, then the burden of persua-
sion shifts to the defendant to prove that it would have taken the same
action even absent any consideration of age. Id. at 1141-42 (citing
Price Waterhouse, 490 U.S. at 258, 259-60, 276).

  Alternatively, the plaintiff may proceed under the pretext frame-
work established in McDonnell Douglas Corp. v. Green, 411 U.S.
792 (1973). Under the McDonnell Douglas framework, the plaintiff
must first prove four elements to make out a prima facie case:

    (1) that she is a member of a protected class; (2) that she
    suffered an adverse employment action; (3) that at the time
    of the adverse employment action she was performing at a
    level that met her employer’s legitimate job expectations;
    and (4) that the position remained open to or was filled by
    similarly qualified applicants outside the protected class.

Brinkley v. Harbour Recreation Club, 180 F.3d 598, 607 (4th Cir.
1999). If the plaintiff proves these four elements, she has established
a presumption of discrimination. Id. The defendant can rebut this pre-
                 KOZLOWSKI v. HAMPTON SCHOOL BOARD                        7
sumption by producing evidence of a legitimate, non-discriminatory
reason for its actions. Id. If the defendant meets this burden, then the
presumption disappears and the plaintiff bears the ultimate burden of
proving discrimination. Id.

   In the past, the plaintiff qualified for the mixed-motive framework,
which has been called "more advantageous" to the plaintiff because
she has the opportunity to shift the burden of persuasion to the defen-
dant, only when she presented "direct evidence" of discrimination.
See Fuller, 67 F.3d at 1141-42. In a recent decision, Desert Palace,
Inc. v. Costa, 539 U.S. ___, 123 S.Ct. 2148 (2003), the Supreme
Court eliminated this "direct evidence" requirement in Title VII cases,
holding that in order to qualify for a mixed-motive instruction, "a
plaintiff need only present sufficient evidence [be it direct or circum-
stantial] for a reasonable jury to conclude, by a preponderance of the
evidence, that ‘race, color, religion, sex, or national origin was a moti-
vating factor for any employment practice.’" Id. at 2155 (quoting 42
U.S.C. § 2000e-2(m)).

   In this case we are not asked to address — and do not address —
whether Desert Palace, a Title VII case, also applies to age discrimi-
nation cases under the ADEA. As we conclude below, the plaintiff
received the benefit of the more advantageous mixed-motive instruc-
tion in this case. Accordingly, the court’s instruction satisfied Desert
Palace even if that decision applies to the ADEA. With this in mind,
we now turn to the plaintiff’s objections to the court’s jury charge on
these two frameworks.

                                    1.

   The plaintiff first argues that the district court erred by refusing to
provide a requested mixed-motive instruction, and thereby deprived
him of the benefit of the more advantageous mixed-motive proof
scheme established in Price Waterhouse. The plaintiff requested two
instructions related to a mixed-motive theory of the case. First, the
plaintiff requested an instruction stating that if the plaintiff proves that
age was a substantial motivating factor in Pearson’s decision not to
renew Kozlowski’s contract, then the burden of persuasion shifts to
the defendant to show that it would have made the same decision even
absent discriminatory animus. The court provided this instruction.
8                KOZLOWSKI v. HAMPTON SCHOOL BOARD
Thus, contrary to the plaintiff’s assertion, it is clear that he did receive
the benefit of a mixed-motive instruction.

   Second, the plaintiff requested, but the court refused to provide, an
instruction on "direct evidence" of discrimination. This instruction
attempted to identify for the jury the specific types of evidence that
constituted "direct evidence." This second instruction was unneces-
sary and would have added confusion to an already complicated
instruction. The court did give the instruction — standard in all cases
— that "the law makes no distinction between direct and circumstan-
tial evidence but simply requires that the jury find from the facts in
accordance with the preponderance of all the evidence in a case, both
direct and circumstantial." The instruction as a whole conveyed the
correct impression that the jury needed to determine, considering both
direct and circumstantial evidence, whether the Board failed to renew
Kozlowski’s contract because of age. The court properly refused to
give the plaintiff’s second requested instruction, and the plaintiff’s
objections in this regard are without merit.

                                     2.

   Apart from these mixed-motive instructions, the plaintiff proposed
a series of three jury instructions based on the McDonnell Douglas
pretext framework, and the plaintiff’s second objection arises in this
portion of the instruction. The first proposed instruction stated that the
plaintiff had an "initial burden of proof" to establish, "by a preponder-
ance of the evidence," that he was a member of the protected class,
that the Board failed to renew his coaching contract, that he was qual-
ified for his job at the time, and that the Board replaced him with a
substantially younger coach. The second instruction explained that the
burden then shifts to the Board to articulate a legitimate, non-
discriminatory reason for the non-renewal.2 The third instruction
    2
   This instruction as proposed was flawed in two respects. First, the
instruction did not clarify whether this shifting burden was one of pro-
duction or of persuasion. As discussed below, this burden is simply one
of production. See infra part II.A.2. Second, because the shifting burden
is one of production, this instruction should not have been given at all.
See id.
                 KOZLOWSKI v. HAMPTON SCHOOL BOARD                        9
stated that if the Board met this burden, the plaintiff had to introduce
evidence that the Board’s purported reasons were pretextual.

   Over the objection of the plaintiff, the district court modified the
first instruction — relating to the prima facie case — to the effect that
Kozlowski had to present evidence not only that the Board failed to
renew his coaching contract, but that the Board failed to renew it "be-
cause of plaintiff’s age." The court’s modification resulted in an
incorrect statement of the prima facie case under McDonnell Douglas.
Cf. Brinkley, 180 F.3d at 607 (listing the four elements of the prima
facie case). The modified instruction injected the ultimate factual
question in an ADEA case — whether the adverse employment action
was because of age — into the prima facie case. We agree with
Kozlowski that the court misstated the elements of the plaintiff’s
prima facie case.

   To assess the impact of this misstatement of the prima facie case,
however, we must first consider the function of the prima facie case
in the McDonnell Douglas pretext framework. In this framework, the
prima facie case serves two functions in the ordering of evidence and
burdens. First, the prima facie case serves as a hurdle to the plaintiff,
albeit a low one. This effect is seen both at the summary judgment
stage and at trial. At summary judgment, if the plaintiff has failed to
produce evidence from which a reasonable fact-finder could find the
existence of the four elements of the prima facie case, then the court
will award judgment to the defendant. See Mitchell v. Data General
Corp., 12 F.3d 1310, 1361 (4th Cir. 1993), modified on other
grounds, Stokes v. Westinghouse Savannah River Co., 206 F.3d 420,
429-30 (4th Cir. 2000). Even if the plaintiff has survived summary
judgment by presenting evidence that could lead a fact-finder to find
the existence of all four factors, at trial the plaintiff must actually per-
suade the fact-finder, by a preponderance of the evidence, that the
four elements of the prima facie case are present. St. Mary’s Honor
Ctr. v. Hicks, 509 U.S. 502, 510 n.3 (1993). If the jury does not credit
the plaintiff’s evidence relating to the prima facie case and finds that
one or more of the four elements is unproven, then its verdict must
be for the defendant regardless of the defendant’s ability to present
evidence of a legitimate, non discriminatory reason for its actions. Id.;
Gafford v. General Elec. Co., 997 F.2d 150, 168 (6th Cir. 1993).
10               KOZLOWSKI v. HAMPTON SCHOOL BOARD
   The second function of the prima facie case is to create a presump-
tion of discrimination, albeit one that is usually easy to overcome.
Once the plaintiff proves the elements of the prima facie case (either
at summary judgment or at trial), discrimination is presumed unless
the defendant can present evidence of a legitimate, non-
discriminatory reason for its actions. St. Mary’s, 509 U.S. at 509.
Importantly, the defendant’s burden here is merely one of production,
not persuasion. To overcome the presumption of discrimination, the
defendant is not required to prove that it had a legitimate, non-
discriminatory reason for its actions, but simply to present evidence
from which a reasonable fact-finder could conclude that the defendant
acted based on a legitimate, non-discriminatory reason. See Reeves v.
Sanderson Plumbing Prods., Inc., 530 U.S. 133, 142 (2000). If the
defendant fails to meet this burden of production by "fail[ing] to
introduce evidence which, taken as true, would permit the conclusion
that there was a nondiscriminatory reason for the adverse action,"
then the plaintiff is entitled to judgment simply by proving the prima
facie case. St. Mary’s, 509 U.S. at 509.3

   Because the defendant’s burden is one of production, that burden
"is an issue solely for determination by the court," not by the jury.
Watson v. Southeastern Penn. Transp. Auth., 207 F.3d 207, 221 (3d
Cir. 2000). See also St. Mary’s, 509 U.S. at 509 ("[T]he burden-of-
production determination necessarily precedes the credibility-
assessment stage."). Accordingly, a jury should never be instructed on
the defendant’s burden of production. See Watson, 207 F.3d at 221.
If the defendant meets this burden of production by presenting evi-
  3
    If the defendant fails to meet its burden of production, the plaintiff has
the opportunity to prevail both at summary judgment and at trial. When
the defendant fails to meet its burden and "any rational person would
have to find the existence of facts constituting a prima facie case," then
the plaintiff is entitled to summary judgment. St. Mary’s, 509 U.S. at
509. In contrast, if "reasonable minds could differ as to whether a pre-
ponderance of the evidence establishes the facts of a prima facie case,"
then the case will be submitted to the trier of fact solely on the elements
of the prima facie case. Id. at 509-10. If the finder of fact determines that
the plaintiff has proven the elements of the prima facie case, then the
presumption of discrimination is established and the verdict must be for
the plaintiff. Id. at 510 n.3.
                KOZLOWSKI v. HAMPTON SCHOOL BOARD                      11
dence of a legitimate, non-discriminatory reason, the presumption cre-
ated by the prima facie case "drops from the case," U.S. Postal Serv.
Bd. of Governors v. Aikens, 460 U.S. 711, 715 (1983), or "disap-
pears," Sandstad v. CB Richard Ellis, Inc., 309 F.3d 893, 897 (5th
Cir. 2002). To put it another way, once the court is satisfied that the
defendant has met its burden of production, there is no longer any
presumption of discrimination and "the trier of fact proceeds to decide
the ultimate question: whether plaintiff has proved that the defendant
intentionally discriminated against [him]." St. Mary’s, 509 U.S. at 511
(quotations and citations omitted) (alteration in original).

   This brings us to evaluating the effect in this case of the court’s
improper modification of the requested prima facie case instruction.
By inserting "because of age" into the prima facie case, the court
made the plaintiff’s initial hurdle more difficult — instead of simply
needing to prove background circumstances where discrimination
might be inferred, the court required the plaintiff to prove the ultimate
issue in the case, namely whether Pearson acted because of age. And
by making this hurdle more difficult, the court correspondingly made
it more difficult for the plaintiff to receive the benefit of the presump-
tion of discrimination that accompanies the establishment of the
prima facie case. Because it is undisputed that the Board met its bur-
den of production, however, neither of these effects prejudiced
Kozlowski’s case. Pearson testified as to a number of legitimate, non-
discriminatory reasons for the non-renewal, and the Board presented
other evidence, including contemporaneous documents, which also
reflected those reasons. The task of determining whether any of those
legitimate reasons actually motivated Pearson was for the jury.

   Once the Board met its burden of production, the sole issue for the
jury in this case was "the ultimate question [of] whether plaintiff has
proved that the defendant intentionally discriminated against [him]
because of his" age. St. Mary’s, 509 U.S. at 511 (citations and quota-
tions omitted) (first alteration added). Because this was the only ques-
tion for the jury, it would make no difference whether the jury
understood this issue to be part of the plaintiff’s initial burden, the
plaintiff’s ultimate burden, or both. Kozlowksi was not prejudiced by
the additional element inserted into the prima facie case, because that
element, which he bore the burden to prove, was the sole element at
issue in the case. Under the court’s improper instruction, the jury was
12              KOZLOWSKI v. HAMPTON SCHOOL BOARD
under the correct assumption that the plaintiff bore the burden of
proving, by a preponderance of the evidence, that Pearson did not
renew Kozlowski’s contract because of his age.

   In addition, because the Board met its burden of production, "[t]he
presumption [of discrimination], having fulfilled its role of forcing the
defendant to come forward with some response, simply drop[ped] out
of the picture," and "the shifted burden of production became irrele-
vant." Id. at 510-11, 507. Kozlowski was not deprived of the benefit
of the prima facie case’s presumption of discrimination, because that
presumption disappeared once the Board had presented evidence of
a legitimate, non-discriminatory reason for his non-renewal. Any
unnecessary confusion that the jury may have encountered in figuring
out the interplay among the elements of the prima facie case, the
defendant’s burden of production, and the plaintiff’s ultimate burden
of proving discrimination is attributable primarily to the improper and
needlessly complex jury instructions requested by the plaintiff in the
first instance. In light of all of this, we conclude that the court’s mis-
statement of the elements of the McDonnell Douglas prima facie
case, standing alone, was harmless error.4

                                    3.

   Kozlowski next argues that the court erred by refusing to instruct
the jury that if it did not believe the reasons given by Pearson for the
non-renewal, then it could infer, but need not infer, that age was the
  4
   In contrast, when the defendant fails to meet its burden of production,
a misstatement of the prima facie case may well be substantially prejudi-
cial. If the Board had failed to offer any evidence of a legitimate, non-
discriminatory reason for its actions, then the only issue in the case
would have been whether Kozlowski had established the prima facie
case. St. Mary’s, 509 U.S. at 509-510. Because the elements of the prima
facie case were uncontested, Kozlowski would have been entitled to
summary judgment. If the court had additionally required Kozlowski to
prove that the non-renewal was "because of age," the case would have
erroneously proceeded to the jury, which might have found against
Kozlowski. This would have deprived Kozlowski of the benefit of the
presumption of discrimination, which, in this scenario, would have been
outcome-determinative.
                KOZLOWSKI v. HAMPTON SCHOOL BOARD                      13
real reason for the decision. Kozlowksi argues that this instruction
was particularly important in this case, because the jury asked about
this issue during its deliberations. Specifically, the jury asked the
court, "By virtue of exclusion of defense’s reasons for nonrenewal,
must we conclude under the law that age discrimination has
occurred?" When discussing this question with counsel, the court ini-
tially indicated that its answer would be no. After some discussion,
however, the court decided simply to repeat the general instruction
without addressing the question specifically.

   Kozlowksi’s requested instruction is a correct statement of the law.
See Reeves, 530 U.S. at 147-48. Different courts have taken varied
approaches, however, on the question of whether a court is required
to instruct a jury on the inference of discrimination that may be drawn
from disbelief of the employer’s stated reasons for its actions. At least
three circuits have held, or implied in dicta, that an instruction on this
permissible inference is required, at least in cases where it appears
from the evidence that the jury may doubt the employer’s stated rea-
sons for its actions, and that the failure to provide the instruction in
such circumstances may constitute reversible error. See Townsend v.
Lumbermens Mut. Cas. Co., 294 F.3d 1232, 1236-41 (10th Cir. 2002)
(holding); Smith v. Borough of Wilkinsburg, 147 F.3d 272, 279-80 (3d
Cir. 1998) (holding); Cabrera v. Jakabovitz, 24 F.3d 372, 382 (2d Cir.
1994) (dicta). In addition, the Eleventh Circuit has quoted positively
from both Smith and Cabrera in support of the proposition that a jury
should be instructed on this permissible inference. See Palmer v. Bd.
of Regents of the Univ. Sys. of Ga., 208 F.3d 969, 974-75 (11th Cir.
2000). The Eleventh Circuit ultimately determined that the plaintiff in
Palmer could not demonstrate that she "was prejudiced by the trial
court’s refusal to deliver the specific instructions proposed by her."
Id. at 975. Accordingly, the court found no reversible error, although
it suggested that the circuit’s Committee on Pattern Jury Instructions
might want to revisit the issue. Id.

   In contrast, the Seventh Circuit has held that while this instruction
may be given, it is not required and a court does not commit error in
refusing to provide it. See Gehring v. Case Corp., 43 F.3d 340, 343
(7th Cir. 1994). The court explained that:

     [While the plaintiff’s requested instruction] is a correct
     statement of the law, . . . a judge need not deliver instruc-
14               KOZLOWSKI v. HAMPTON SCHOOL BOARD
      tions describing all valid legal principles. Especially not
      when the principle in question describes a permissible, but
      not an obligatory, inference. Many an inference is permissi-
      ble. Rather than describing each, the judge may and usually
      should leave the subject to the argument of counsel. . . .
      Instructions on the topic were unnecessary.

Id. Similarly, the Eighth Circuit has held that this instruction need not
be given in a case where the "evidence . . . provides little to create
a fact issue on pretext," and added in dicta that "[w]e do not express
any view as to whether it ever would be reversible error for a trial
court to fail to give a pretext instruction, though we tend to doubt it."
Moore v. Robertson Fire Protection Dist., 249 F.3d 786, 790 & n.9
(8th Cir. 2001).5 The First Circuit has likewise expressed doubt, in
dicta, "that such an explanation is compulsory, even if properly
requested." Fite v. Digital Equipment Corp., 232 F.3d 3, 7 (1st Cir.
2000).

   We agree with the general principle that a judge need not instruct
a jury on all valid legal principles in a given case. Nonetheless, the
particular inference at issue here — that if the jury disbelieves the rea-
sons given by the employer to justify its actions, then the jury may
infer discrimination — has in the past sparked considerable disagree-
ment among the courts. Prior to Reeves, courts took a variety of
approaches to when and if evidence of the prima facie case, combined
with evidence tending to disprove the employer’s stated reason for its
actions, would suffice to permit a jury to determine that the real rea-
son behind the employer’s actions was discrimination. See Reeves,
530 U.S. at 140-41 (listing cases adopting various approaches). In
Reeves the Supreme Court clarified that "a plaintiff’s prima facie
case, combined with sufficient evidence to find that the employer’s
asserted justification is false, may permit the trier of fact to conclude
that the employer unlawfully discriminated." Id. at 148. Given the
amount of disagreement among judges of the federal courts of appeals
over whether a jury may infer discrimination simply from their disbe-
  5
   It is worth noting that the Eighth Circuit in Moore did not state, even
in dicta, that it would never be erroneous for a court to fail to instruct
a jury on this permissible inference. Rather, the court merely expressed
doubt that such an error would be reversible. Id.
                KOZLOWSKI v. HAMPTON SCHOOL BOARD                     15
lief of the employer’s stated justifications, it seems unlikely that
jurors will uniformly intuit that such an inference is permissible. As
the Tenth Circuit stated, "[t]his is a difficult matter for courts, and
would certainly be difficult for a jury." Townsend, 294 F.3d at 1241.
See also Smith, 147 F.3d at 280-81 ("In light of the decades it has
taken for the courts to shape and refine the McDonnell Douglas stan-
dard into its present form and the inordinate amount of ink that has
been spilled over the question of how a jury may use its finding of
pretext, it would be disingenuous to argue that it is nothing more than
a matter of common sense.").

   We do not suggest that a court in a pretext case must always
instruct jurors that they may, but need not, infer discrimination from
their disbelief of an employer’s stated reasons. Rather, we hold that
when the evidence presented at trial creates some likelihood that the
jury might disbelieve the legitimate, non-discriminatory reasons given
by the employer to justify its actions, then the jury should be
instructed on this permissible inference. The majority of circuit courts
that have considered this question agree that at least in these circum-
stances, this instruction should be given. See Townsend, 294 F.3d at
1241; Smith, 147 F.3d at 279-80; Cabrera, 24 F.3d at 382-83; Palmer,
208 F.3d at 974-75. That said, an erroneous failure to give this
instruction when circumstances call for it will not always require
reversal. Rather, the court’s failure to give this instruction, even when
erroneous, is still subject to harmless error review. See Townsend, 294
F.3d at 1241. Cf. United States v. Lewis, 53 F.3d 29, 32 (4th Cir.
1995) (finding that, in the criminal context, a court’s refusal to pro-
vide a requested instruction is reversible only when prejudicial, even
when the instruction is correct and not otherwise covered in the
instruction).

   Turning to the case at hand, we conclude that the court erred by
refusing to provide some form of the plaintiff’s requested instruction
that "[i]f you do not believe the Defendant’s explanation for its
actions, then you may infer, but need not infer, that . . . the Defendant
intentionally discriminated against [the Plaintiff] because of age."
Evidence presented by the plaintiff undermined at least some of the
reasons that Pearson had given to explain his decision not to renew
Kozlowski’s contract. For example, Pearson claimed that Bernie
West, the stepfather of one of Kozlowski’s football players, Tim
16               KOZLOWSKI v. HAMPTON SCHOOL BOARD
Smith, had complained to Pearson that Kozlowski had refused to pro-
vide him with game films that Smith needed to show to college
recruiters. West testified differently, stating that he had expressed
concern to Pearson about being able to get game films at some future
point, but that he never complained about Kozlowski and in fact had
never requested any films. Pearson also stated that Glenn Price, the
father of Jason Price, had complained to him that Kozlowski had
threatened to dismiss Jason from the team because he did not have a
signed note excusing him from practice. Glenn Price testified that he
had never spoken with Pearson about any such incident. Pearson’s
testimony as to several other incidents was also undermined by
Kozlowski’s evidence.

   It was up to the jury to determine whether the plaintiff’s evidence
on these matters was credible, and how directly that evidence under-
mined Pearson’s stated reasons. But in light of this evidence, this is
not a case where the "evidence . . . provides little to create a fact issue
on pretext." Moore, 249 F.3d at 790. The jurors’ question during
deliberations about how they were permitted to draw inferences in the
event that they disbelieved Pearson further illustrates that the plaintiff
had presented a meaningful amount of evidence suggesting pretext. In
this situation, the district court erred in refusing to instruct the jurors
that if they disbelieved the reasons given by Pearson, they could infer,
but need not infer, that the real reason for the non-renewal was
Kozlowski’s age.

   Although the district court erred here, this error warrants reversal
only if it "seriously prejudiced the challenging party’s case." S. Atl.
Ltd. P’ship of Tenn. v. Riese, 284 F.3d 518, 530 (4th Cir. 2002).
Because we determine in part IV, infra, that Kozlowski is entitled to
a new trial due to the collective weight of this and the other errors,
we decline to determine whether this error alone would warrant rever-
sal.

                                    B.

   The plaintiff next challenges the district court’s use of the phrase
"solely because of age" in the jury charge. The plaintiff did not object
to this modification at trial, so we review for plain error. When a
party fails to object to a jury instruction, "[w]e are prepared to reverse
                KOZLOWSKI v. HAMPTON SCHOOL BOARD                        17
. . . [for plain error] only when we can conclude that a particular jury
instruction must necessarily have caused the jury to act in complete
ignorance of, or to have misapplied, fundamentally controlling legal
principles to the inevitable prejudice of an aggrieved party." Spell v.
McDaniel, 824 F.2d 1380, 1395 (4th Cir. 1987).

   The plaintiff requested the general instruction that the ADEA
"makes it unlawful to refuse to hire or discharge any individual
because of such individual’s age." The court modified the instruction
in two ways. First, it changed "discharge" to "renew any employment
contract" so as to conform the instruction to the facts of this case.
Second, the court inserted the word "solely," so that the instruction
read that the plaintiff had to prove that the Board did not renew his
contract "solely because of his age."

    The court’s addition of the term "solely" was erroneous. "It is clear
. . . that the law requires only that age be a causative or determinative
factor in the decision, not the sole reason." Smith v. Univ. of N.C., 632
F.2d 316, 337 (4th Cir. 1980). Nonetheless, in order to constitute
plain error, this error "must necessarily have caused the jury to act in
complete ignorance of, or to have misapplied, fundamentally control-
ling legal principles to the inevitable prejudice of an aggrieved party."
Spell, 824 F.2d at 1395. In this case, the court repeated the phrase
"solely because of age" four times, twice during the original instruc-
tion and twice during follow-up instructions after questions from the
jury. While the court repeated the term "solely" four times, it did not
elaborate on the meaning of that term. In contrast, the court correctly
instructed the jury a number of times, and at length, that age had to
be a determining factor in the decision not to renew. For example, the
court correctly explained that the Board is not liable if

    it would have taken the same action even in the absence of
    discriminatory intent. This means that . . . even if it put aside
    the discriminatory intent or if discriminatory intent did not
    exist at all, the defendant would have taken the same
    adverse action against the plaintiff. In other words the
    defendant [is not liable if] . . . its legitimate reasons standing
    alone would have induced it to make the same decision. In
    this particular case, the defendant acted on the recommenda-
    tion of the principal. This means that in the case you must
18               KOZLOWSKI v. HAMPTON SCHOOL BOARD
      find . . . that the principal would have still made the same
      decision to recommend the nonrenewal of Dennis
      Kozlowski’s contract even if he was not motivated by a
      desire to have younger coaches.

The judge repeated this extended explanation several times. Given
this repeated, detailed, and extended explanation of the correct causa-
tion standard, we think it likely that the jury decided the case under
the more fully explained (and correct) requested instruction that age
must be the determining factor, the court’s use of the term "solely"
notwithstanding. Cf. Cabrera, 24 F.3d at 384 ("Because of the
Court’s extensive and repeated instructions that the plaintiff bore the
burden of proving discrimination, we believe that the jury could not
have been led astray by the Court’s brief comment to the contrary.").
Certainly we cannot conclude that the court’s instruction as a whole
on the issue of causation "caused the jury to act in complete ignorance
of, or to . . . misappl[y], fundamentally controlling legal principles to
the inevitable prejudice of an aggrieved party." Spell, 824 F.2d at
1395. The court’s insertion of the term "solely" into the instructions,
when taken in light of the extended and correct explanation of the
determinative cause standard, does not rise to the level of plain error.6
  6
   In light of our ultimate decision to remand for a new trial, we note
two other errors in the jury instructions that the plaintiff has not raised
on appeal. During one of the court’s descriptions of the burden-shifting
scheme, the court stated that once the plaintiff made out the prima facie
case, the School Board must articulate a legitimate, non-discriminatory
reason for its actions. The court then instructed that "[t]he School Board
does not have to persuade you of this fact by a preponderance of the evi-
dence. Instead, the School Board is required only to produce enough evi-
dence in contradiction of plaintiff’s claim to create a genuine issue of
fact in your mind." This is a serious error — the court seems to be saying
that so long as the Board introduces enough evidence to create a genuine
issue of fact in the minds of the jurors, then the Board should prevail.
This error helps illustrate why a jury should never be instructed on a
party’s burden of production. It is true that a burden of production is met
when a party introduces evidence sufficient to create a genuine issue of
material fact. But this is a determination that is always in the province
of the court, never the jury. The jury’s task is to decide close questions
of fact, not to figure out when the evidence creates a close question.
Because the plaintiff does not raise this error on appeal, however, we do
not consider it as part of our decision to remand.
                 KOZLOWSKI v. HAMPTON SCHOOL BOARD                       19
                                    III.

   In addition to his challenges to the jury instructions, the plaintiff
raises two evidentiary challenges and one challenge to the court’s
refusal to sequester a witness. The plaintiff objects to the court’s
exclusion of evidence related to alleged prior similar acts of discrimi-
nation by Pearson and to the court’s admission of evidence related to
his prior arrests for driving under the influence of alcohol. Finally, he
challenges the court’s refusal to sequester Pearson, a main defense
witness, during the course of the trial. We will address these issues
one at a time.

                                    A.

   Kozlowski argues that the district court erred in excluding his prof-
fered evidence of alleged prior similar acts of age discrimination by
Pearson. We review challenges to the court’s admission or exclusion
of evidence for abuse of discretion. United States v. Sitt, 250 F.3d
878, 888 (4th Cir. 2001). When the court has committed an error
regarding the admission or exclusion of evidence, that error is subject
to harmless error review. See Taylor v. Va. Union Univ., 193 F.3d
219, 234-35 (4th Cir. 1999).

  Plaintiff’s counsel proffered testimony showing that in April of
1994, Pearson replaced three coaches, ages 43, 52, and 46, with youn-

   Second, during one of the follow-up instructions the court stated that
"[i]n discrimination cases if there is a legitimate reason for an action to
be taken and there is an improper and unlawful reason for an action to
be taken both of which are established by a preponderance of the evi-
dence, the defendant is entitled to judgment." This is incorrect. If age is
a determinative factor in the decision, then the presence of another, legit-
imate factor does not absolve the defendant of liability. The court went
on to add that the plaintiff must show that "the primary reason" for his
non-renewal was his age. This is a bit closer, although it is imprecise and
therefore potentially misleading. The phrase "primary reason" seems to
imply that the jury should look at the reasons and see which was the
"most important," or something to that effect. This is a different test than
whether age was a but-for cause. Again, the plaintiff has not raised this
error, so we do not consider it.
20              KOZLOWSKI v. HAMPTON SCHOOL BOARD
ger coaches, ages 31, 33, and 20-something. According to the plain-
tiff’s proffer, "Dennis Kozlowski and Frank Brown, a football trainer,
would have testified that [prior to replacing these three coaches] Prin-
cipal Pearson stated that, quote, He wanted younger coaches at Bethel
and that it was time for new blood, unquote." The plaintiff also
argued that the evidence would have shown that the reasons given by
Pearson for those replacements were false. The district court excluded
this testimony, explaining that these events were five years removed
from Kozlowski’s non-renewal, that they involved "some other mat-
ters within the school system," and that they would not be relevant to
the case at hand. The court explained that it "was unwilling to allow
a principal’s entire career at the school to be subjected to review for
the purpose of establishing in 1998 and 1999 an act of discrimination
against Mr. Kozlowski."

   In a somewhat different context, we have held that a district court
abused its discretion by excluding evidence of the contemporaneous
use of racial slurs by members of a fire department, which were prof-
fered to show that the plaintiff, a black man, was not hired due to his
race. See Mullen v. Princess Anne Volunteer Fire Co., 853 F.2d 1130,
1132-35 (4th Cir. 1988). We stated generally that "[t]he principle is
well-established that prior acts and statements should be admitted
where necessary to show state of mind." Id. at 1133. We cited favor-
ably to Hunter v. Allis-Chalmers Corp., 797 F.2d 1417, 1423 (7th Cir.
1986), a case holding that evidence of past incidents of harassment
unrelated to the specific disputed action were properly admissible to
show race-based intent. Id. at 1134.7 In addition, other courts have
generally held that evidence of similar alleged acts of discrimination,
or other acts which reveal a discriminatory attitude generally, are
admissible to show a defendant’s intent in acting against the plaintiff.
See, e.g., Robinson v. Runyon, 149 F.3d 507, 512-13 (6th Cir. 1998)
(holding that in race discrimination case, district court abused its dis-
cretion by excluding a "racist [mock] employment application, which
was circulated and allegedly known to upper level management, yet
  7
   The court in Mullen nonetheless affirmed the jury verdict for the
defendant fire company, holding that the exclusion was harmless because
of overwhelming evidence that the plaintiff’s physical infirmities pre-
vented him from performing the job of a fireman. Mullen, 853 F.2d at
1135-36.
                KOZLOWSKI v. HAMPTON SCHOOL BOARD                      21
not immediately condemned, [as the application] plainly makes the
existence of racially motivated actions by management of the CBMC
more probable."); Polanco v. City of Austin, 78 F.3d 968, 980 (5th
Cir. 1996) (noting that evidence of discriminatory practices against
Hispanics in the workplace was probative of whether individual plain-
tiff was terminated because of his nationality); Spulak v. K Mart
Corp., 894 F.2d 1150, 1156 (10th Cir. 1990) ("As a general rule, the
testimony of other employees about their treatment by the defendant
is relevant to the issue of the employer’s discriminatory intent." (list-
ing cases)); Estes v. Dick Smith Ford, Inc., 856 F.2d 1097, 1102 (8th
Cir. 1988) (holding that in case where plaintiff claimed that he was
fired from Ford dealership because of his race and age, district court
erred in "prevent[ing] Estes from presenting the jury with evidence
that Ford excluded blacks from its workforce, that Ford had fired two
other employees specifically because of their ages, that Ford’s service
department offered free rides to white customers while black custom-
ers were told to rent cars, and that members of Ford’s management
referred to blacks as ‘niggers.’"), abrogated on other grounds, Price
Waterhouse v. Hopkins, 490 U.S. 228 (1989).

   The defendant argues that it was proper to exclude the proffered
testimony because it was too removed in time and because admission
of the evidence would have simply resulted in duplicative and time-
consuming "mini-trials" where the plaintiff and the defendant would
have litigated whether the prior non-renewals were motivated by age,
just as they were litigating the issue in this case. The cases cited by
the defendant in support of the court’s exclusion here, however, are
quite distinguishable from the case at hand.

   In this circuit, the defense relies on Patterson v. McLean Credit
Union, 805 F.2d 1143 (4th Cir. 1986), aff’d in part, vacated in part,
491 U.S. 164 (1989). In Patterson, the plaintiff brought suit under 42
U.S.C. § 1981 for racial harassment and for being discharged because
of her race. Id. at 1144. The district court correctly dismissed her
racial harassment claim, ruling that claims of general racial harass-
ment, unconnected to some adverse employment action, was not cog-
nizable under § 1981. Id. at 1145.8 At trial on her discriminatory
  8
   This ruling was affirmed on appeal first by this court, id. at 1145-46,
and then by the U.S. Supreme Court, Patterson v. McLean Credit Union,
491 U.S. 164, 176-85 (1989).
22              KOZLOWSKI v. HAMPTON SCHOOL BOARD
discharge claim, the court excluded evidence of racial harassment of
another employee ten years prior to the plaintiff’s own discharge. Id.
at 1147. We affirmed, stating that "[b]ecause of the remoteness in
time of the events to which [the other employee] would have testified,
the probative value of that evidence would have been slight and the
court could properly conclude that its slight value was outweighed by
the likelihood of confusion it might create on the issue on which it
was tendered." Id.

   Patterson is distinguishable from this case in several respects. First
of all, in Patterson the court excluded evidence of general racial
harassment. This evidence was most relevant to Patterson’s racial
harassment claim, which the court properly had dismissed as not cog-
nizable under § 1981. Here, in contrast, the alleged prior acts are of
precisely the same nature as the acts alleged in this suit — a failure
to renew the contract of an older coach, replacement with a younger
coach, and contemporaneous statements that the reason for the non-
renewal was age. Second, the alleged prior harassment in Patterson
was ten years removed from the plaintiff’s non-promotion and layoff,
whereas the acts here are only five years removed.

   The defendant also cites Johnson v. Yellow Freight System, Inc.,
734 F.2d 1304 (8th Cir. 1984). In Johnson, the Eighth Circuit held
that the district court had not abused its discretion in a Title VII race
discrimination case when it refused to allow cross-examination of a
company employee concerning "a petition circulated among black
supervisors [that] . . . alleged discrimination in that black employees
had not been promoted." Id. at 1311. The court did not permit discus-
sion of the petition because "to allow questions raising a new and
unproven claim would necessitate inquiry into the truth or falsity of
the claim. The court [also] noted that the petition was circulated three-
and-one-half years after Johnson’s termination." Id. The main differ-
ence between Johnson and this case is that here, the evidence of prior
age discrimination is directly probative of Pearson’s motivation —
the testimony would have been that Pearson said he was not renewing
prior contracts because the coaches were too old. In contrast, in John-
son the petition was directly probative only of a perception of dis-
crimination among certain black supervisors, not of the fact that
actual discrimination existed.
                KOZLOWSKI v. HAMPTON SCHOOL BOARD                    23
   We recognize that at some point, prior acts of discrimination or dis-
criminatory statements are sufficiently removed in time and/or simi-
larity from the current dispute that their probative value is slim and
their exclusion justifiable. In this case, however, the potential proba-
tive value of these prior acts was more than slight. It is an open ques-
tion whether the jury would have credited the testimony of the
plaintiff and of Frank Brown, a football trainer who had also been
replaced by Pearson. But if the jury had credited the testimony, these
prior acts of age discrimination would have been highly probative of
Pearson’s motivation in this case. We also recognize that the scope
of the plaintiff’s proffered testimony may have been overly broad.
The plaintiff proffered evidence not only of the non-renewals and the
contemporaneous age-related statements, but also evidence allegedly
disproving the reasons that Pearson would have given for those non-
renewals. The defense is likely correct that allowing the plaintiff the
opportunity to prove, person by person, that in each case Pearson’s
purported reasons for non-renewal were false would have required
lengthy and cumbersome mini-trials. This process would have
required, for each non-renewed individual, testimony from Pearson
about why, five years earlier, he had refused to renew that coach’s
contract, rebuttal evidence and/or testimony from the plaintiff show-
ing that those reasons were false, and reply evidence and/or testimony
from the Board further justifying Pearson’s decision. We find no error
in the court’s decision to exclude this type of evidence, which would
have been quite time-consuming and would have distracted the jury
from the central issue in this case, namely whether Pearson had failed
to renew Kozlowski’s contract because of age.

   In contrast with the proffer of evidence attempting to disprove
Pearson’s reasons for his non-renewal of the three coaches in 1994,
Kozlowski’s evidence of Pearson’s past age-related comments would
have been relatively simple to present and rebut, and, if credited,
highly probative as to Pearson’s intent. It appears that the defendant
did not contest the fact that the three coaches had been replaced by
younger coaches, so the rebuttal evidence would have consisted sim-
ply of testimony by Pearson denying making these discriminatory
statements. The jury would then have been left to make credibility
determinations about this testimony, just as it was required to make
a credibility determination regarding Kozlowski’s and Pearson’s con-
24              KOZLOWSKI v. HAMPTON SCHOOL BOARD
flicting testimony about their December 4 conversation about
Kozlowski’s non-renewal.

   In sum, the presentation of this evidence would not have required
extended "mini-trials." The testimony related to essentially identical
instances of alleged discriminatory non-renewals and bore directly on
Pearson’s motivations. The prior acts were less than five years
removed from Kozlowski’s non-renewal, and were performed by the
same individual, Pearson, whose motivation was in question here. We
conclude that in these circumstances, the court abused its discretion
in refusing to admit the limited evidence of Pearson’s alleged prior
statements of discriminatory intent.

   Even though it was error to exclude this evidence, the question
remains whether that error was harmless. The court in Mullen held
that the exclusion was harmless because there was overwhelming evi-
dence that the plaintiff lacked the physical capability to be a fireman.
Mullen, 853 F.2d at 1135-36. Here, the evidence is closer. As
explained in detail in part II.A.3, the plaintiff presented evidence
rebutting some of Pearson’s purported legitimate reasons for the non-
renewal. Furthermore, during the course of the jury’s deliberations,
the jury asked the court whether it must infer discrimination if it did
not believe Pearson’s stated reasons. This question demonstrates that
at least some of the jurors had serious doubts about whether they
believed any of Pearson’s stated legitimate reasons. On the other
hand, it also seems apparent from the jury’s verdict that they did not
credit Kozlowski’s testimony about his meeting with Pearson. It is
questionable whether similar testimony from Kozlowski about prior
events would have buttressed his case. It is more difficult to conjec-
ture about whether the jury would have credited similar testimony
from Frank Brown. In the end, we need not decide whether this error
alone would warrant reversal. It is enough to say, as we conclude in
part IV, that this error, in combination with the other errors we iden-
tify in this opinion, substantially prejudiced Kozlowski’s case.

                                  B.

   The plaintiff also challenges the district court’s admission, over
objection, of evidence that Kozlowski had been arrested several times
for driving under the influence of alcohol. Evidence was also intro-
                 KOZLOWSKI v. HAMPTON SCHOOL BOARD                      25
duced showing that Kozlowski was acquitted of these charges.
Kozlowski objected that the DUI evidence was prejudicial and irrele-
vant, because his DUI arrests were not one of the reasons given by
Pearson for his non-renewal. The Board conceded at trial, and con-
cedes on appeal, that Pearson did not consider Kozlowski’s DUI
arrests in making his decision. The Board argues, however, that at
least one of the Board members indicated that Kozlowski’s DUI
arrests and related adverse publicity may have been a factor in his
perception of Kozlowski’s ability to continue coaching. The court
admitted the evidence on this ground, noting that while Pearson made
the initial decision not to renew the contract, that decision was ratified
by the Board.

   The critical question, then, is whether the Board’s liability in this
case depended solely on the motivation of Pearson (in which case the
DUI evidence was irrelevant, and its admission error) or whether the
motivation of the Board members themselves might also have been
relevant to the Board’s liability. Under the court’s own jury instruc-
tions, it was error to admit this evidence. The court instructed the jury
that "[i]n this particular case, the decision not to renew plaintiff’s con-
tract was made by the School Board on the recommendation of its
agent, Principal David Pearson. If you find that Principal Pearson’s
recommendation was because of the age of Dennis Kozlowski, then
you must hold the School Board liable for the acts of its agent, David
Pearson." The court essentially instructed the jury that the Board
members’ personal motivations in ratifying Pearson’s decision were
not relevant — if Pearson was improperly motivated by age, then the
Board was liable. The ADEA, like Title VII, imposes liability on an
"employer" who acts with the proscribed motive. Both statutes define
"employer" to include "any agent of" the employer. See 29 U.S.C.
§ 630(b) (West 2003) (ADEA); 42 U.S.C. § 2000e(b) (West 2003)
(Title VII). In applying this agency standard, the Supreme Court held
that an employer is liable for the discriminatory acts of a supervisor
who is "principally responsible" for an adverse employment action or
who is the "actual decisionmaker," even if that supervisor does not
make the "formal decision." Reeves, 530 U.S. at 151-52. Here, both
parties agree that Pearson was Kozlowski’s direct supervisor, that the
School Board had delegated its authority to not renew coaching con-
tracts to Pearson, and that Pearson was the actual decisionmaker in
26                KOZLOWSKI v. HAMPTON SCHOOL BOARD
the non-renewal of Kozlowski’s contract.9 Accordingly, if Pearson
failed to renew the contract because of age, the Board is liable regard-
less of the subjective intents of the Board members.

   The court therefore correctly instructed the jury to focus solely on
the intent of Pearson in failing to renew Kozlowksi’s contract. Under
this instruction, evidence related solely to the motives of School
Board members was irrelevant to any issue that was material to the
case. The only impact the DUI evidence could have had on the jury,
then, was to improperly prejudice them against Kozlowski. As with
the exclusion of the evidence of prior similar acts of discrimination,
we need not decide whether this error, standing alone, would warrant
reversal. Rather, this error provides yet another reason, in combina-
tion with the other errors discussed herein, to find that a retrial is war-
ranted.

  9
   James Haggard, the School Board chairman, testified as follows about
the decision-making authority here:
      — "The School Board is ultimately responsible for the hiring
      of all school personnel. That responsibility is then delegated
      down to the superintendent of schools and then for supplemental
      contracts further delegated down to the building administrators,
      so in the case of Mr. Kozlowski, it would have been within the
      scope of authority of the principal of the Bethel High School to
      award that supplement [contract] for the year." JA 146.
      — "It was the Board’s belief that it was certainly within the
      scope of authority of the principal at Bethel High School to make
      that decision for renewal or nonrenewal." JA 150.
      — "[I]n the decision not to renew Coach Kozlowski’s supple-
      mental coaching contract, the Board made a decision not to get
      involved in that because the Board’s belief was that the responsi-
      bility and duty had been delegated to the principal of the school,
      . . . Mr. Pearson." JA 548.
According to this evidence, even if the Board was the formal decision-
maker in this case, it took that formal action based solely on Pearson’s
recommendation, which it accepted as conclusive. This shows that Pear-
son was principally responsible for the decision.
                 KOZLOWSKI v. HAMPTON SCHOOL BOARD                       27
                                    C.

   The final objection raised by the plaintiff is the court’s denial of
his motion to sequester Pearson from the trial. "We review de novo
the district court’s order refusing sequestration or sequestering a per-
son whom it finds exempt under section . . . (2) [an officer or
employee of a party which is not a natural person designated as its
representative by its attorney], and we review for clear error factual
findings about who is a party, officer, or employee." Opus 3 Ltd. v.
Heritage Park, Inc., 91 F.3d 625, 628 (4th Cir. 1996). Furthermore,
"we construe the rule’s exemptions narrowly in favor of the party
requesting sequestration," and "the party seeking to avoid sequestra-
tion of a witness bears the burden of proving that a Rule 615 exemp-
tion applies." Id. (quotations and citations omitted).

  Under Rule 615 of the Federal Rules of Evidence,

     [a]t the request of a party the court shall order witnesses
     excluded so that they cannot hear the testimony of other wit-
     nesses. . . . This rule does not authorize exclusion of . . . (2)
     an officer or employee of a party which is not a natural per-
     son designated as its representative by its attorney, or (3) a
     person whose presence is shown by a party to be essential
     to the presentation of the party’s cause. . . .

Fed. R. Evid. 615. Before trial, plaintiff’s counsel requested that Pear-
son be excluded, noting that Rule 615(2) applies only to officers or
employees, and that Pearson had retired and was no longer employed
by the Board. Before permitting the Board an opportunity to respond,
the court ruled that "if he is going to be designated as the representa-
tive for the City because of his involvement in the case, I will let him
sit at counsel table with counsel for the trial. That will not mean that
[the defendant] may then have a member of the School Board. He will
be the sole representative."

   From this ruling, it does not appear that the court made a factual
finding that Pearson was, at the time of the trial, still an officer or
employee of the Board.10 Rather, it appears that the court interpreted
   10
      If the court had made such a factual finding, that finding would be
clearly erroneous. Pearson himself testified at trial that he retired from
the Board’s employment in June of 2000, over a year before the trial
began.
28              KOZLOWSKI v. HAMPTON SCHOOL BOARD
Rule 615(2) to include a former officer or employee who is meaning-
fully involved in the case. This interpretation contradicts the text of
the rule, which plainly refers to "an officer or employee" but makes
no mention of a former officer or employee. Obviously, a corporate
defendant cannot itself be present, so Rule 615(2) allows a corporate
defendant to designate one of its current employees or officers to
attend the trial and not to be excluded. But just as a natural person
may not designate her most important witness as her representative at
trial, a corporate defendant cannot designate its most important wit-
ness simply because he is a former officer or employee.

   On appeal, the Board argues in the alternative that Pearson’s pres-
ence at trial can be justified under part (3) of Rule 615, which pro-
vides an exception for "a person whose presence is shown by a party
to be essential to the presentation of the parties’ cause." We are
doubtful that the court’s ruling against sequestration was based on this
exception — certainly the Board made no showing of necessity, and
the court made no findings to that effect. To satisfy the exception, a
party must show, among other things, that the "the witness’s presence
is ‘essential’ rather than simply desirable." United States v. Jackson,
60 F.3d 128, 135 (2d Cir. 1995). Putting aside the Board’s failure to
present any evidence or argument to the district court regarding Pear-
son’s "essential" role in its presentation of its case, the Board’s argu-
ments on appeal still fall far short of establishing that Pearson’s
presence at trial was anything more than convenient for the Board.
Thus, the court erred in refusing to sequester Pearson.

   Our prior cases make clear our reluctance to find harmless a court’s
erroneous refusal to sequester a witness, particularly an important fact
witness. In Opus 3 Ltd. v. Heritage Park, Inc., 91 F.3d 625 (1996),
we noted that Rule 615 "is designed to discourage and expose fabrica-
tion, inaccuracy, and collusion," and explained that "sequestering wit-
nesses ‘is (next to cross-examination) one of the greatest engines that
the skill of man has ever invented for the detection of liars in a court
of justice.’" 91 F.3d at 628 (quoting 6 John H. Wigmore, Wigmore on
Evidence § 1838, at 463 (James H. Chadbourn ed., 1976)). When the
individual in question is a key fact witness, "adherence to the seque-
stration rule is most important." Opus, 91 F.3d at 629. In United
States v. Farnham, 791 F.2d 331 (4th Cir. 1986), we explained our
reluctance to find a sequestration error harmless:
                KOZLOWSKI v. HAMPTON SCHOOL BOARD                    29
    [W]e understand the mandatory, unambiguous language of
    the rule to reflect the drafters’ recognition that any defen-
    dant in Farnham’s position would find it almost impossible
    to sustain the burden of proving the negative inference that
    the second agent’s testimony would have been different had
    he been sequestered. A strict prejudice requirement of this
    sort would be not only unduly harsh but also self-defeating,
    in that it would swallow a rule carefully designed to aid the
    truth-seeking process and preserve the durability and accept-
    ability of verdicts.

Farnham, 791 F.3d at 335. Despite our rejection of a strict prejudice
requirement in Farnham, we later clarified that "violations of Fed. R.
Evid. 615 are subject to the harmless error rule." United States v. Har-
ris, 39 F.3d 1262, 1268 (4th Cir. 1994) (citation omitted). We noted
our willingness to presume prejudice "where it would be impossible
for the defendant to prove that the [non-sequestered witness’s] testi-
mony would have been different if he had not heard the first agent’s
testimony." Id. Nonetheless, we explained that "[w]e have no need to
presume prejudice to the defendants here because we are satisfied in
the case before us that the discussions that took place between the
witnesses had no substantial influence on the jury verdict." Id.
Accordingly, we have found reversible error in cases where it is
impossible to tell whether the non-sequestered witness would have
testified differently in a manner that would have materially affected
the trial. This means that the appellee does not bear the burden to
affirmatively demonstrate prejudice, as is usually the case on appeal.
Nonetheless, we have also made clear that an error in non-
sequestration does not warrant per se reversal — if the circumstances
of a particular case illustrate clearly that the witness in question did
not tailor his testimony, or that the witness’s testimony had no sub-
stantial influence on the verdict, we may find the error harmless.

   In this case, the Board argues that we can find lack of prejudice
based on several factors. First, Pearson had written down the reasons
for the non-renewal in letters to Kozlowski and the Board and had
been deposed at length. Any tailoring of his testimony could have
been brought out by contrasting it with his prior writings and deposi-
tion testimony. Second, as noted above in part II.A.3, it appears that
the plaintiff was able to successfully cast doubt on much of Pearson’s
30               KOZLOWSKI v. HAMPTON SCHOOL BOARD
testimony. This would indicate that Pearson was not able to — or
simply did not — tailor his testimony so as to suck the wind from the
plaintiff’s case.

   On the other hand, the plaintiff argues convincingly that Pearson
nonetheless was able to tailor his responses to the plaintiff’s rebuttal
witnesses and therefore rehabilitate potentially discredited earlier tes-
timony. When Pearson was recalled as a witness after having previ-
ously testified, defense counsel started by stating that "[y]ou’ve had
the opportunity as you’ve sat [in the trial] over the last couple of days
to hear the testimony of various witnesses." Defense counsel then
asked Pearson to respond directly to much of the contradictory testi-
mony that he had observed. This is precisely the situation that Rule
615 was designed to prevent. When a witness is properly sequestered,
that witness loses his ability to re-characterize his testimony in light
of damaging contradictory testimony by other witnesses or to explain
away inconsistencies. Here, Pearson was given that opportunity. We
decline to decide whether this error standing alone would warrant
reversal, but conclude that the error, in combination with the other
errors we identify in this opinion, substantially prejudiced
Kozlowski’s case.

                                   IV.

   After reviewing Kozlowski’s various grounds for appeal, we have
concluded that the district court committed at least four non-forfeited
errors to the detriment of Kozlowski.11 Specifically, the court erred
by: (1) failing to instruct the jury that it could infer age discrimination
from the falsity of the defendant’s proffered reasons; (2) excluding
evidence proffered by the plaintiff of prior similar alleged acts of age
discrimination; (3) admitting evidence related to Kozlowski’s past
DUI arrests; and (4) failing to sequester Pearson, a primary defense
witness, from the trial proceedings. We have identified certain of
these errors that would not, standing alone, warrant reversal, and we
have withheld judgment about the individual harmlessness of the
  11
      Our analysis here does not include the district court’s insertion of
"because of age" into the instruction that was based on the McDonnell
Douglas prima facie case because that error did not prejudice the plain-
tiff.
                KOZLOWSKI v. HAMPTON SCHOOL BOARD                      31
remaining errors. As a number of courts have recognized, however,
the collective force of multiple errors can, in some instances, warrant
reversal even when one or two of the errors standing alone would not.
See Frymire-Brinati v. KPMG Peat Marwick, 2 F.3d 183, 188 (7th
Cir. 1993) ("One or two of these errors might have been excused as
harmless. Collectively, however, they presented the jury such a
skewed picture that the verdict is unreliable and must be set aside.");
Malek v. Fed. Ins. Co., 994 F.2d 49, 55 (2d Cir. 1993) ("Although any
one of the above evidentiary errors standing alone may have been
harmless and would not mandate reversal, the cumulative effect of
these errors substantially prejudiced the Maleks’ case."); Gordon
Mailloux Enterprises, Inc. v. Firemen’s Ins. Co. of Newark, N. J., 366
F.2d 740, 742 (9th Cir. 1966). But see SEC v. Infinity Group Co., 212
F.3d 180, 196 (3d Cir. 2000) (rejecting cumulative error doctrine in
civil context). Although we have not yet had the occasion to consider
the cumulative error doctrine in the civil context, we have applied the
doctrine in the criminal context. See United States v. Martinez, 277
F.3d 517, 532 (4th Cir. 2002). We have also rejected the notion that
a different standard should apply for harmless error review in the civil
context than in the criminal context. See Taylor v. Va. Union Univ.,
193 F.3d 219, 235 (4th Cir. 1999). Accordingly, we will now consider
the cumulative effect of the errors we have identified.

   An error is harmless when it does not affect the appellant’s "sub-
stantial rights." Id. Put differently, an error is harmless when the court
can say "with fair assurance, after pondering all that happened with-
out stripping the erroneous action from the whole, that the judgment
was not substantially swayed by the errors." Id. (quotations and cita-
tions omitted). Given the number of the errors in this case and the
seriousness of at least some of those errors, such as the court’s failure
to sequester the defendant’s main fact witness, we conclude that the
cumulative effect of the errors was substantially prejudicial to
Kozlowski’s case. The errors affected both the evidence that the jury
was permitted to consider as well as the legal standard that the jury
was asked to apply to that evidence. The court’s evidentiary and
sequestration errors meant that the jury was unaware of probative evi-
dence of alleged prior similar acts of discrimination; was aware of
Kozlowski’s irrelevant DUI arrests, which cast him in a negative
light; and heard testimony from the defendant’s main fact witness,
Pearson, that was quite possibly tailored to meet the contrary evi-
32              KOZLOWSKI v. HAMPTON SCHOOL BOARD
dence of the plaintiff. In addition, the court failed to inform the jury
of an important inference that the law, as has become clear only
recently, permits them to draw. When we consider the trial in light of
these errors, we cannot say "with fair assurance . . . that the judgment
was not substantially swayed by the errors." Id. (quotations and cita-
tions omitted). We conclude that the errors preserved by the plaintiff
and raised on appeal substantially affected his case and were not harm-
less.12 Accordingly, we vacate the judgment of the district court and
remand for a new trial.

                                        VACATED AND REMANDED
  12
    Because we conclude that the cumulative effect of the non-forfeited
errors warrants reversal, we need not decide whether we would ever con-
sider the effect of any forfeited errors when conducting a cumulative
effect review.
