                            District of Columbia
                             Court of Appeals
No. 14-CV-1350
                                                                      OCT 20 2016
MOTOROLA INC., et al.,
                                                Appellants,

     v.                                                              CAB-8479-01


MICHAEL PATRICK MURRAY, et al.,
                                                Appellees.


             On Appeal from the Superior Court of the District of Columbia
                                   Civil Division


     BEFORE: WASHINGTON, Chief Judge; and GLICKMAN, FISHER, BLACKBURNE-
RIGSBY, THOMPSON, BECKWITH, and EASTERLY, Associate Judges.

                                    JUDGMENT

               This case came to be heard on the transcript of record and the briefs filed,
and was argued en banc by counsel. On consideration whereof, and as set forth in the
opinion filed this date, it is now hereby

               ORDERED and ADJUDGED that the judgments on appeal are remanded
for further proceedings consistent with this opinion.


                                          For the Court:




Dated: October 20, 2016.

Opinion by Associate Judge John Fisher.

Concurring opinion by Associate Judge Catharine Easterly.
Notice: This opinion is subject to formal revision before publication in the
Atlantic and Maryland Reporters. Users are requested to notify the Clerk of the
Court of any formal errors so that corrections may be made before the bound
volumes go to press.

            DISTRICT OF COLUMBIA COURT OF APPEALS

                                No. 14-CV-1350                         10/20/16

                      MOTOROLA INC., et al., APPELLANTS,

                                       V.

                 MICHAEL PATRICK MURRAY, et al., APPELLEES.

                         Appeal from the Superior Court
                          of the District of Columbia
                                (CAB-8479-01)

                   (Hon. Frederick H. Weisberg, Trial Judge)

(Argued En Banc November 24, 2015                              October 20, 2016)

      Terrence J. Dee argued for appellants.

      James F. Green and Jeffrey B. Morganroth argued for appellees.

     Many additional counsel were on the briefs for the parties or filed briefs
amicus curiae. Their names are listed in an appendix to this opinion.

     Before WASHINGTON, Chief Judge, and GLICKMAN, FISHER, BLACKBURNE-
RIGSBY, THOMPSON, BECKWITH, and EASTERLY, Associate Judges.

      Opinion for the court by Associate Judge FISHER.

      Concurring opinion by Associate Judge EASTERLY at page 20.
                                         2

      FISHER, Associate Judge: For decades this court has used the Dyas/Frye

test1 to govern the admissibility of expert testimony. We now are sitting en banc to

consider whether we should abandon that test in favor of the standards embodied in

Rule 702 of the Federal Rules of Evidence. For the reasons explained below, we

adopt Rule 702.2



                   I. The Factual and Procedural Background



      The plaintiffs in these thirteen cases have sued numerous cell phone

manufacturers, service providers, and trade associations, alleging that long-term

exposure to cell-phone radiation causes brain tumors.          Judge Frederick H.

Weisberg held four weeks of evidentiary hearings on the admissibility of the expert

testimony offered by the plaintiffs. 3 He concluded that, based on the present


      1
         See Dyas v. United States, 376 A.2d 827 (D.C. 1977); Frye v. United
States, 293 F. 1013 (D.C. Cir. 1923).
      2
          In the absence of legislation prescribing rules of evidence, “this court is
the final authority for establishing the evidentiary rules for the Superior Court of
the District of Columbia.” Laumer v. United States, 409 A.2d 190, 195 n.7 (D.C.
1979) (en banc).
      3
         Judge Weisberg heard “testimony from plaintiffs’ eight experts and
defendants’ four rebuttal experts, received approximately 280 exhibits containing
thousands of pages of documents, and reviewed hundreds of pages of legal briefing
both before and after the hearing.”
                                            3

record, “some, but not all, of Plaintiffs’ proffered expert testimony on general

causation is admissible under the Frye/Dyas evidentiary standard,” but “most, if

not all, of Plaintiffs’ experts would probably be excluded under the Rule

702/Daubert standard . . . .”4 Judge Weisberg then certified the following question

of law for interlocutory appeal: “whether the District of Columbia should adopt

Federal Rule of Evidence 702 (or a revised Frye standard) for the admissibility of

expert evidence.”      See D.C. Code § 11-721 (d) (2012 Repl.).            We granted

appellants’ motion for interlocutory review.5



                                   II. Legal Analysis



          Our role at this stage of the proceedings is limited, but consequential. It is

not our task to affirm or reverse Judge Weisberg’s ruling.6 For this reason, we will


      4
          Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993).
      5
         The statute governing our jurisdiction permits an interlocutory appeal in a
civil case when a judge of the Superior Court states in writing his or her opinion
“that the ruling or order involves a controlling question of law as to which there is
substantial ground for a difference of opinion and that an immediate appeal from
the ruling or order may materially advance the ultimate termination of the litigation
or case.” D.C. Code § 11-721 (d). This court may, in its discretion, permit the
appeal to be taken. Id.; see also In re J.A.P., 749 A.2d 715, 717 (D.C. 2000).
      6
          Appellants note that their appeal “does not challenge any specific findings
related to a particular expert.” Brief for Appellants at 8.
                                         4

not attempt to duplicate his learned discussion of the underlying science or his

extended summary of the testimony he heard. Instead, we must decide whether to

change the legal standard that governs the admission of expert testimony.



                                A. The Dyas/Frye Test



      In this jurisdiction, the admission of expert testimony has been governed by

the legal principles set forth in Frye v. United States and Dyas v. United States. In

the seminal case of Frye, the trial court excluded evidence that the defendant had

taken and passed an early form of a lie-detector test. 293 F. 1013. Upholding the

ensuing murder conviction, the Court of Appeals of the District of Columbia

articulated a test for admitting expert testimony. That test was thereafter widely

adopted in federal and state courts:



             Just when a scientific principle or discovery crosses the
             line between the experimental and demonstrable stages is
             difficult to define. Somewhere in this twilight zone the
             evidential force of the principle must be recognized, and
             while courts will go a long way in admitting expert
             testimony deduced from a well-recognized scientific
             principle or discovery, the thing from which the
             deduction is made must be sufficiently established to
             have gained general acceptance in the particular field in
             which it belongs.
                                           5


Id. at 1014.



      Later, in Dyas, we expanded upon Frye and adopted a three-part test for

determining whether to admit expert testimony:



               (1) the subject matter “must be so distinctively related to
               some science, profession, business or occupation as to be
               beyond the ken of the average layman”; (2) “the witness
               must have sufficient skill, knowledge, or experience in
               that field or calling as to make it appear that his opinion
               or inference will probably aid the trier in his search for
               truth”; and (3) expert testimony is inadmissible if “the
               state of the pertinent art or scientific knowledge does not
               permit a reasonable opinion to be asserted even by an
               expert.”



376 A.2d at 832 (quoting McCormick on Evidence, § 13 at 29-31 (E. Cleary, 2d ed.

1972)). “The third criterion [of Dyas] incorporates the . . . Frye test, under which

scientific testimony is admissible only if the theory or methodology on which it is

based has gained general acceptance in the relevant scientific community.” (John)

Jones v. United States, 990 A.2d 970, 977 (D.C. 2010).



      “[B]ecause expert or scientific testimony possesses an aura of special

reliability and trustworthiness, the proffer of such testimony must be carefully
                                           6

scrutinized.” Ibn-Tamas v. United States, 407 A.2d 626, 632 (D.C. 1979) (internal

quotation marks and citation omitted). However, under Dyas/Frye, this inquiry

“begins—and ends—with a determination of whether there is general acceptance

of a particular scientific methodology, not an acceptance, beyond that, of particular

study results based on that methodology.” Id. at 638; see also President and

Directors of Georgetown College v. Wheeler, 75 A.3d 280, 291 (D.C. 2013) (“The

third Dyas requirement focuses not on the acceptance of a particular conclusion

derived from the methodology, but rather on the acceptance of the methodology

itself.” (ellipsis, brackets, and internal quotation marks omitted)).



       “General acceptance means just that; the answer cannot vary from case to

case.” (Nathaniel) Jones v. United States, 548 A.2d 35, 40 (D.C. 1988). “If the

technique has gained such general acceptance, we will accept it as presumptively

reliable and thus generally admissible into evidence.”         Id. at 39.   As Judge

Weisberg explained, under the Dyas/Frye test “the question of whether an expert

used a particular generally accepted methodology correctly is not at issue when

determining the . . . admissibility” of the expert’s testimony. See, e.g., United

States v. Porter, 618 A.2d 629, 636 (D.C. 1992) (“Any failure by the scientists to

adhere to the appropriate procedure is, of course, a proper subject of inquiry, but

does not raise an issue which implicates Frye.”).
                                           7



                               B. The Daubert Trilogy



      In 1993 the Supreme Court held that the “general acceptance” test had been

superseded by the Federal Rules of Evidence, which were enacted half a century

after Frye was decided. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S.

579, 587 (1993).       Accordingly, “[t]hat austere standard, absent from, and

incompatible with, the Federal Rules of Evidence, should not be applied in federal

trials.” Id. at 589. Interpreting Rule 702, the “specific” rule governing expert

testimony, the decision in Daubert in some respects relaxed traditional barriers to

opinion testimony. Id. at 588 (“[A] rigid general acceptance requirement would be

at odds with the liberal thrust of the Federal Rules and their general approach of

relaxing the traditional barriers to opinion testimony.” (internal quotation marks

omitted)). The Court emphasized, however, that “the trial judge must [still] ensure

that any and all scientific testimony or evidence admitted is not only relevant, but

reliable.” Id. at 589. Here, of course, the Court was referring “to evidentiary

reliability—that is, trustworthiness.” Id. at 590 n.9.



      Therefore, when a party proffers expert scientific testimony, the trial court

must make “a preliminary assessment of whether the reasoning or methodology
                                         8

underlying the testimony is scientifically valid and of whether that reasoning or

methodology properly can be applied to the facts in issue.” 509 U.S. at 592-93.

Although it eschewed “a definitive checklist or test,” id. at 593, the Court in

Daubert did suggest factors to be considered, including whether the theory or

technique has been tested, whether it “has been subjected to peer review and

publication,” “the known or potential rate of error,” and “the existence and

maintenance of standards controlling the technique’s operation.” Id. at 593-94.

“Finally, ‘general acceptance’ can yet have a bearing on the inquiry.” Id. at 594.

Nevertheless, the Court cautioned, the inquiry is “a flexible one.” Id. “The focus

. . . must be solely on principles and methodology, not on the conclusions that they

generate.” Id. at 595.



      The Court made clear that it did not intend for the trial judge’s more refined

gatekeeping role to displace the normal tools of the adversary system. “Vigorous

cross-examination, presentation of contrary evidence, and careful instruction on the

burden of proof are the traditional and appropriate means of attacking shaky but

admissible evidence.” 509 U.S. at 596. “[I]n practice,” however, “a gatekeeping

role for the judge, no matter how flexible, inevitably on occasion will prevent the

jury from learning of authentic insights and innovations.” Id. at 597.
                                          9

      The Court also pointed out that Rule 702 does not operate in isolation. To

perform the gatekeeping function, the trial court normally will apply Rule 104 (a)

(preliminary questions, such as whether a witness is qualified or evidence is

admissible); Rule 703 (the bases of an expert’s opinion); and Rule 403 (permitting

the exclusion of relevant evidence “if its probative value is substantially

outweighed by a danger of one or more of the following: unfair prejudice,

confusing the issues, misleading the jury, undue delay, wasting time, or needlessly

presenting cumulative evidence”).7 509 U.S. at 592-95. When discussing Rule

403, the Court endorsed this explanation: “Expert evidence can be both powerful

and quite misleading because of the difficulty in evaluating it. Because of this risk,

the judge in weighing possible prejudice against probative force under Rule 403 of

the present rules exercises more control over experts than over lay witnesses.” 509

U.S. at 595 (quoting Hon. Jack B. Weinstein, Rule 702 of the Federal Rules of

Evidence Is Sound; It Should Not Be Amended, 138 F.R.D. 631, 632 (1991)).




      7
         This court has adopted Rule 703 (In re Melton, 597 A.2d 892, 901 & n.10
(D.C. 1991) (en banc)), and Rule 403 (Johnson v. United States, 683 A.2d 1087,
1100 (D.C. 1996) (en banc)). Although we have not formally adopted Rule 104,
“it accurately states the rule of evidence we generally follow.” Jenkins v. United
States, 80 A.3d 978, 991 (D.C. 2013).
                                          10

      Expressing confidence “that federal judges possess the capacity to undertake

this review [of expert testimony for evidentiary reliability],” 509 U.S. at 593, the

Court summarized:



              “General acceptance” is not a necessary precondition to
              the admissibility of scientific evidence under the Federal
              Rules of Evidence, but the Rules of Evidence—
              especially Rule 702—do assign to the trial judge the task
              of ensuring that an expert’s testimony both rests on a
              reliable foundation and is relevant to the task at hand.
              Pertinent evidence based on scientifically valid principles
              will satisfy those demands.



Id. at 597.



      In two subsequent decisions, the Supreme Court refined its analysis in

Daubert, now acknowledging that “conclusions and methodology are not entirely

distinct from one another.” General Electric Co. v. Joiner, 522 U.S. 136, 146

(1997). “[N]othing in either Daubert or the Federal Rules of Evidence requires a

district court to admit opinion evidence that is connected to existing data only by

the ipse dixit of the expert.” Id. Thus, “[a] court may conclude that there is simply

too great an analytical gap between the data and the opinion proffered.” Id. The

abuse of discretion standard of review applies, regardless of whether the trial court

decided “to admit or exclude scientific evidence.” Id.
                                          11



      “Daubert’s general holding—setting forth the trial judge’s general

‘gatekeeping’ obligation—applies not only to testimony based on ‘scientific’

knowledge, but also to testimony based on ‘technical’ and ‘other specialized’

knowledge.” Kumho Tire Co. v. Carmichael, 526 U.S. 137, 141 (1999) (quoting

Fed. R. Evid. 702). Moreover,



             the test of reliability is “flexible,” and Daubert’s list of
             specific factors neither necessarily nor exclusively
             applies to all experts or in every case. Rather, the law
             grants a district court the same broad latitude when it
             decides how to determine reliability as it enjoys in
             respect to its ultimate reliability determination.



Id. at 141-42. In other words, “the trial judge must have considerable leeway in

deciding in a particular case how to go about determining whether particular expert

testimony is reliable.” Id. at 152. The objective of the gatekeeping requirement “is

to make certain that an expert . . . employs in the courtroom the same level of

intellectual rigor that characterizes the practice of an expert in the relevant field.”

Id.



      Daubert and its progeny thus focus not only on methodology, as Frye and

Dyas do, but also on the application of that methodology in a particular case. As
                                          12

the Court explained in Kumho Tire, “Rule 702 grants the district judge the

discretionary authority, reviewable for its abuse, to determine reliability in light of

the particular facts and circumstances of the particular case.” 526 U.S. at 158.

Applying this principle, the Court concluded in both Joiner and Kumho Tire that

the trial court had not abused its discretion by excluding the proffered expert

testimony. See Joiner, 522 U.S. at 146-47; Kumho Tire, 526 U.S. at 158. It is thus

fair to say that the impact of the Daubert trilogy has been mixed: These cases

relax the initial barriers to the admission of expert testimony, but at the same time

emphasize the trial judge’s robust gatekeeping function.



                                C. Rule 702, Amended



      Although the Daubert trilogy represented the Supreme Court’s construction

of Rule 702, that rule and its commentary were in turn amended (in 2000) to reflect

the Supreme Court’s guidance. Rule 702 (as amended stylistically in 2011) now

provides:



                    A witness who is qualified as an expert by
             knowledge, skill, experience, training, or education may
             testify in the form of an opinion or otherwise if:
                    (a) the expert’s scientific, technical, or other
             specialized knowledge will help the trier of fact to
             understand the evidence or to determine a fact in issue;
                                         13

                     (b)   the testimony is based on sufficient facts or
             data;
                   (c) the testimony is the product of reliable
             principles and methods; and
                   (d) the expert has reliably applied the principles
             and methods to the facts of the case.



Fed. R. Evid. 702. In making our decision, we will focus on this articulation of the

governing principles.



                             D. Why We Adopt Rule 702



      The parties and amici have recommended three options for our

consideration:   (1) retain the Dyas/Frye test, by which we currently abide;

(2) adopt Federal Rule 702, as amended to reflect the Daubert trilogy; or (3) craft a

revised version of the Dyas/Frye test. There are many criticisms of the first two

tests. On the one hand, critics of Dyas/Frye claim that it is antiquated and out-of-

step with modern science. It avoids, even forbids, looking at the crucial question

of whether the testimony offered in a particular case is reliable. Some say that

Frye forces unqualified jurors to decide which scientific theories should be applied

to the particular case.    One court has concluded that Frye “is both unduly

restrictive and unduly permissive.” State v. Coon, 974 P.2d 386, 394 (Alaska

1999). “[I]t excludes scientifically reliable evidence which is not yet generally
                                         14

accepted, and admits scientifically unreliable evidence which although generally

accepted, cannot meet rigorous scientific scrutiny.” Id. at 393-94. Judge Weisberg

also concluded that Frye “is not a good gatekeeper for inductive sciences such as

epidemiology or psychology.”



      On the other hand, Rule 702 and Daubert are faulted for producing

inconsistent results, for making unqualified judges evaluate the work of scientists,

and for invading the province of the jury. We acknowledge that following a

uniform rule does not ensure uniform results. There are many trial judges and

many types of science.      Moreover, the criteria for determining reliability are

flexible, and the decisions of trial judges are reviewed only for abuse of discretion.

Some inconsistency is inevitable.



      Having studied the matter at great length, Judge Weisberg expressed his own

conclusion:   “[A]t the risk of over-simplification[,] if a reliable, but not yet

generally accepted, methodology produces ‘good science,’ Daubert will let it in,

and if an accepted methodology produces ‘bad science,’ Daubert will keep it out;

conversely, under Frye, as applied in this jurisdiction, even if a new methodology

produces ‘good science,’ it will usually be excluded, but if an accepted

methodology produces ‘bad science,’ it is likely to be admitted.”
                                          15



      Our choice boils down to this: Like the “general acceptance” test, Rule 702

is concerned with the reliability of the “principles and methods” applied by the

expert. Fed. R. Evid. 702 (c). But Rule 702 (d) goes further and expressly requires

the court to determine whether “the expert has reliably applied the principles and

methods to the facts of the case.” We conclude that Rule 702, with its expanded

focus on whether reliable principles and methods have been reliably applied, states

a rule that is preferable to the Dyas/Frye test. 8 The ability to focus on the

reliability of principles and methods, and their application, is a decided advantage

that will lead to better decision-making by juries and trial judges alike.



      We have considered revising the Frye test, as some jurisdictions have done,9

but there are substantial benefits to be gained from adopting a test that is widely

used. See Johnson v. United States, 683 A.2d 1087, 1100 (D.C. 1996) (en banc)

(noting “the advantage that uniformity with the federal rule and the vast majority

      8
          Our decision to adopt Rule 702 means, among other things, that we will
no longer ask whether the subject matter is “beyond the ken of the average
layman.” Dyas, 376 A.2d at 832. The proper inquiry is whether “the expert’s
scientific, technical, or other specialized knowledge will help the trier of fact to
understand the evidence or to determine a fact in issue.” Fed. R. Evid. 702 (a).
      9
         See, e.g., Blackwell v. Wyeth, 971 A.2d 235, 241-43, 250-56 (Md. 2009);
Cornell v. 360 West 51st St. Realty, LLC, 9 N.E.3d 884, 896-97 (N.Y. 2014); Betz
v. Pneumo Abex LLC, 44 A.3d 27, 58 (Pa. 2012).
                                         16

of state rules affords for interpretation and application”). We can learn from the

decisions of other courts which apply Rule 702 or its state counterparts.

Nevertheless, we are not proceeding with any illusions that the cases are uniform

or even consistent. Nor will the transition be easy. But we are not the first

jurisdiction to make this change, and the Advisory Committee Notes to Rule 702

provide helpful guidance for applying the rule. Echoing sentiments from Daubert,

509 U.S. at 593, we are confident that judges of the Superior Court, like their

Article III counterparts, are fully capable of performing the gatekeeping function.



                                E. Applying Rule 702



      Properly performing the gatekeeping function will require a delicate touch.

“[T]he trial court’s role as gatekeeper is not intended to serve as a replacement for

the adversary system.” Fed. R. Evid. 702 advisory committee’s notes to 2000

amendments (quoting United States v. 14.38 Acres of Land Situated in Leflore

County, Mississippi, 80 F.3d 1074, 1078 (5th Cir. 1996)). But, as Joiner and

Kumho Tire clearly demonstrate, the trial court will have the discretion (informed

by careful inquiry) to exclude some expert testimony.          The goal is to deny

admission to expert testimony that is not reliable, but to admit competing theories

if they are derived from reliable principles that have been reliably applied.
                                          17



      “When a trial court, applying [Rule 702], rules that an expert’s testimony is

reliable, this does not necessarily mean that contradictory expert testimony is

unreliable. [Rule 702] is broad enough to permit testimony that is the product of

competing principles or methods in the same field of expertise.” Fed. R. Evid. 702

advisory committee’s notes to 2000 amendments. Indeed, we expect that many

cases will feature expert witnesses espousing different views of the evidence.

Their testimony will be tested by the adversary process and evaluated by the jury.



      What about cases in which the experts on one side are in a distinct minority?

That may well raise a red flag, for “[w]hen a scientist claims to rely on a method

practiced by most scientists, yet presents conclusions that are shared by no other

scientist, the [trial] court should be wary that the method has not been faithfully

applied.” Lust v. Merrell Dow Pharmaceuticals, Inc., 89 F.3d 594, 598 (9th Cir.

1996) (cited in Fed. R. Evid. 702 advisory committee’s notes to 2000

amendments). But minority status is not a proxy for unreliability. The trial court

still will need to determine whether the opinion “is the product of reliable

principles and methods[,] . . . reliably applied.” Fed. R. Evid. 702 (c), (d).
                                        18

      One considerable cost of adopting Rule 702 is that judges and lawyers will

have to adjust to new rules. There will also be the question of what to do about

types of expert testimony that have been commonly admitted under Dyas/Frye.

Must this jurisdiction revisit the admissibility of every form of expert testimony?

Both Daubert and the Advisory Committee Notes to Rule 702 provide some useful

guidance.



      There is no “grandfathering” provision in Rule 702. However, Daubert

commented that “‘general acceptance’ can . . . have a bearing on the [reliability]

inquiry.” 509 U.S. at 594. “Widespread acceptance can be an important factor in

ruling particular evidence admissible, and a known technique which has been able

to attract only minimal support within the community may properly be viewed

with skepticism.” Id. (internal quotation marks and citation omitted). Moreover,

“the trial judge has the discretion ‘both to avoid unnecessary “reliability”

proceedings in ordinary cases where the reliability of an expert’s methods is

properly taken for granted, and to require appropriate proceedings in the less usual

or more complex cases where cause for questioning the expert’s reliability arises.’”

Fed. R. Evid. 702 advisory committee’s notes to 2000 amendments (quoting

Kumho Tire, 526 U.S. at 152). What the court may not do is reflexively admit
                                             19

expert testimony because it has become accustomed to doing so under the

Dyas/Frye test.



       Plaintiffs lament the enormous amounts of time and money that have been

spent on discovery and pretrial litigation, and they fault defendants for agreeing to

use the Dyas/Frye test in these cases. But the defendants could not have done

otherwise because Dyas and Frye are binding precedent until revisited by this court

sitting en banc. See M.A.P. v. Ryan, 285 A.2d 310, 312 (D.C. 1971). It is also

highly doubtful that we would have accepted an interlocutory appeal until we were

presented with a developed record. See note 5, above.



       Plaintiffs also argue that any new rule we adopt should not apply to these

cases, but such an outcome would be inconsistent with the very purpose for

entertaining an interlocutory appeal. See note 5, above. Judge Weisberg explained

that if this court adopted a new rule governing the admissibility of expert

testimony, he “could then allow whatever additional discovery might be necessary

to place Plaintiffs in a fair position to litigate that issue.”
                                         20



                                  III. Conclusion



      We adopt Rule 702 to apply to the trial of this case and to any civil or

criminal case10 in which the trial begins after the date of this opinion. We will

consider at a later time, when the issue is properly presented, whether the standard

applies to cases that have already been tried but are not yet final on direct appeal.

See generally Davis v. Moore, 772 A.2d 204 (D.C. 2001) (en banc). These cases

are remanded for further proceedings consistent with this opinion.



                                              It is so ordered.



      EASTERLY, Associate Judge, concurring: I join the opinion of the court

adopting Federal Rule of Evidence 702 as the rule for the admission of expert

testimony in criminal and civil cases. With this decision, trial courts will be called

upon to scrutinize an array of forensic expert testimony under new, more


      10
          The United States Attorney’s Office and the Office of the Attorney
General for the District of Columbia prosecute the criminal cases that are heard in
the Superior Court. The Public Defender Service represents the defendants in
many of those cases. All three offices have filed briefs amicus curiae urging us to
adopt Rule 702. No party or amicus has asked us to adopt a different rule for
criminal cases.
scientifically demanding standards. As the opinion of the court states, “[t]here is

no ‘grandfathering’ provision in Rule 702,” and, under the new rule we adopt,

courts may not “reflexively admit expert testimony because it has become

accustomed to doing so under the Dyas/Frye test.” Ante, at 18–19.



      Fortunately, in assessing the admissibility of forensic expert testimony,

courts will have the aid of landmark reports that examine the scientific

underpinnings of certain forensic disciplines routinely admitted under Dyas/Frye,

most prominently, the National Research Council’s congressionally-mandated

2009 report Strengthening Forensic Science in the United States: A Path

Forward,1 and the President’s Council of Advisors on Science and Technology’s

(PCAST) 2016 report Forensic Science in the Criminal Courts: Ensuring

Scientific   Validity   of   Feature-Comparison    Methods    [hereinafter   PCAST

Report]. 2 These reports provide information about best practices for scientific

testing, an objective yardstick against which proffered forensic evidence can be

measured, as well as critiques of particular types of forensic evidence. In addition,




      1
          Available at https://www.ncjrs.gov/pdffiles1/nij/grants/228091.pdf.
      2
       Available at https://www.whitehouse.gov/sites/default/files/microsites/ost
p/PCAST/pcast_forensic_science_report_final.pdf.
                                        22

the PCAST Report contains recommendations for trial judges performing their

gatekeeping role under Rule 702:

            (A) When deciding the admissibility of [forensic] expert
               testimony, . . . judges should take into account the
               appropriate scientific criteria for assessing scientific
               validity including: (i) foundational validity,[3] with
               respect to the requirement under Rule 702(c) that
               testimony is the product of reliable principles and
               methods; and (ii) validity as applied,[4] with respect
               to [the] requirement under Rule 702(d) that an expert
               has reliably applied the principles and methods to the
               facts of the case.
            (B) . . . [J]udges, when permitting an expert to testify
               about a foundationally valid feature-comparison
               method, should ensure that testimony about the
               accuracy of the method and the probative value of
               proposed identifications is scientifically valid in that
               it is limited to what the empirical evidence
               supports. Statements suggesting or implying greater
               certainty are not scientifically valid and should not be
               permitted. In particular, courts should never permit
               scientifically indefensible claims such as: “zero,”
               “vanishingly small,” “essentially zero,” “negligible,”
               “minimal,” or “microscopic” error rates; “100 percent
               certainty” or proof “to a reasonable degree of
               scientific certainty;” identification “to the exclusion


      3
         “Foundational validity for a forensic-science method requires that it be
shown, based on empirical studies, to be repeatable, reproducible, and accurate, at
levels that have been measured and are appropriate to the intended application.”
PCAST Report, supra, at 4. If a method has foundational validity it “can, in
principle, be reliable.” Id. at 4–5.
      4
         “Validity as applied means that the method has been reliably applied in
practice.” Id. at 5. It means that the expert has “reliably applied . . .
[foundationally valid] principles and methods to the facts of the case.” Id.
                                        23

                of all other sources;” or a chance of error so remote as
                to be a “practical impossibility.”

PCAST Report, supra, at 19; see also id. at 142–45; Gardner v. United States, 140

A.3d 1172, 1184 (D.C. 2016) (imposing limits on experts’ statements of certainty).




      As the opinion of the court explains, the ultimate concern of the courts is

with evidentiary reliability. Ante, at 7. But, “[i]n a case involving scientific

evidence”—or evidence held out as scientific evidence—“evidentiary reliability

will be based on scientific validity.” Daubert v. Merrell Dow Pharm., Inc., 509

U.S. 579, 590 n.9 (1993); see also PCAST Report, supra, at 19 (explaining that

“scientific validity” encompasses both “foundational validity” and “validity as

applied”).
                                        24

                                  APPENDIX


                              LIST OF COUNSEL
       Terrence J. Dee argued for appellants. The following were on the brief:
Laura Sierra, Scott A. Elder (pro hac vice pending), and David Venderbush
(admitted pro hac vice) for appellant Cellco Partnership d/b/a Verizon Wireless,
Bell Atlantic Mobile, Inc., and Verizon Wireless Inc.; Jennifer G. Levy, Terrence
J. Dee (admitted pro hac vice), and Michael B. Slade (admitted pro hac vice) for
appellant Motorola, Inc.; Thomas Watson, Curtis S. Renner, and Lauren Boucher
for appellants AT&T Inc., AT&T Wireless Services Inc., Cingular Wireless LLC,
and related entities; Paul Scrudato (pro hac vice pending) and Thomas M. Crispi
(pro hac vice pending) for appellant Apple Inc., a defendant in other related cases
Nos. 2012 CA 008537 B, 2013 CA 007805 B, 2013 CA 007620 B, and 2014 CA
0004171 B; Seamus C. Duffy (pro hac vice pending) and Michael Daly (pro hac
vice pending) for appellants AT&T Inc., AT&T Wireless Services Inc., Cingular
Wireless LLC, and related entities; Howard N. Feldman for appellant Audiovox
Communications Corporation; Howard D. Scher, Patrick T. Casey, and John
Korns for appellant Cellular One Group; Michael D. McNeely and Vicki L. Dexter
for appellant Cellular Telecommunications & Internet Association; Paul
Farquharson and Scott Phillips for appellant Cricket; Ralph A. Taylor, Jr., and
Rosemarie Ring (admitted pro hac vice in D.C. Superior Court only) for appellant
HTC America, Inc., a defendant in other related cases Nos. 2012 CA 008533 and
2014 CA 002797; Sean Reilly for appellant LG Electronics MobileComm U.S.A.,
Inc., a defendant in other related cases Nos. 2014 CA 002521, 2012 CA 003241,
2012 CA 004068, 2013 CA 007620, 2013 CA 008192, 2014 CA 001425, and 2014
CA 002797; Steven M. Zager, Amanda R. Johnson, Stanley E. Woodward Jr., and
Richard W. Stimson (admitted pro hac vice) for appellant Microsoft Mobile Oy;
Francis A. Citera (pro hac vice pending), Matthew A.C. Zapf (pro hac vice
pending), and Precious Murchison for appellants Qualcomm Inc. and Sony
Electronics Inc.; John B. Isbister and Jaime W. Luse for appellant Samsung
Telecommunications America, LLC; J. Stan Sexton (pro hac vice pending), Patrick
N. Fanning (pro hac vice pending), and John A. Turner, III, for appellants Sprint
Nextel Corporation f/k/a Nextel Communications and Sprint Spectrum, L.P. d/b/a
Sprint PCS; Paul H. Vishny, Paul E. Freehling (admitted pro hac vice), and Rhett
E. Petcher for appellant Telecommunications Industry Association; Michael
Scoville and Mary Rose Hughes for appellant T-Mobile USA, Inc.; and Eugene A.
Schoon (admitted pro hac vice) and Tamar B. Kelber for appellant United States
Cellular Corporation.
                                        25


      James F. Green and Jeffrey B. Morganroth argued for appellees. The
following were on the brief: James F. Green and Michelle A. Parfitt co-counsel
for appellees Prischman, Kidd, Solomon, Brown, and Noroski; Jeffrey B.
Morganroth, Mayer Morganroth, and Jill A. Gurfinkel lead counsel for appellees
Murray, Cochran, Agro, Keller, Schwamb, Schofield, and Bocook, and co-counsel
for Marks; Hunter Lundy, Rudie R. Soileau Jr., and Kristie Hightower lead counsel
for appellees Prischman, Kidd, Solomon, and Brown, and co-counsel for Marks;
Victor H. Pribanic and Matthew Doebler lead counsel for appellee Noroski; Jeffrey
S. Grand co-counsel for appellee Solomon; Laura Bishop Knoll, Jerold Edward
Knoll, Jerold Edward Knoll, Jr., and Edmond H. Knoll co-counsel for appellees;
and Steven R. Hickman co-counsel for appellees.

      Brief of amicus curiae Business and Medical Coalition in support of
appellants was filed by Steven P. Lehotsky and Sheldon Gilbert for Chamber of
Commerce of the United States of America, Amar D. Sarwal for Association of
Corporate Counsel, and Joe G. Hollingsworth and Eric G. Lasker for all amici.

      Brief of amici curiae D.C. Defense Lawyers’ Association and DRI in
support of appellants, reversal, and the adoption of Rule 702 and Daubert to
modernize the standard for admission of expert opinions was filed by Kelly Hughes
Iverson, Kamil Ismail, Craig S. Brodsky, Erin Christen Miller, and Meghan
Hatfield Yanacek for D.C. Defense Lawyers’ Association; and John Parker
Sweeney for DRI – The Voice of the Defense Bar.

      Brief of amicus curiae Product Liability Advisory Council, Inc., in support
of appellants’ request for reversal of order admitting expert testimony was filed by
Terri S. Reiskin, Marilyn S. Chappell, L. Michael Brooks, Jr., Mary A. Wells, and
Hugh F. Young, Jr.

      Brief of amicus curiae Public Defender Service in support of appellants was
filed by James Klein, Alice Wang, Jason Tulley, and Emily Voshell, Public
Defender Service.

     Brief of amicus curiae Trial Lawyers Association of Metropolitan
Washington, D.C., in support of appellees and affirmance was filed by John Vail.

       Joint Brief of amici curiae United States of America and the District of
Columbia in support of appellants was filed by Ronald C. Machen Jr., United
States Attorney at the time the brief was filed, and Elizabeth Trosman and John P.
                                       26

Mannarino, Assistant United States Attorneys; and Karl A. Racine, Attorney
General for the District of Columbia, Todd S. Kim, Solicitor General, and Loren L.
AliKhan, Deputy Solicitor General.
