

                United States Court of Appeals                            United States Court of Appeals
                    For the First Circuit                                For the First Circuit
                                         

No. 94-1258

               WILLIAM AND RITA ESPEAIGNNETTE,

                   Plaintiffs, Appellants,

                              v.

                 GENE TIERNEY COMPANY, INC.,

                     Defendant, Appellee.

                                         

         APPEAL FROM THE UNITED STATES DISTRICT COURT

                  FOR THE DISTRICT OF MAINE

         [Hon. Morton A. Brody, U.S. District Judge]                                                               

                                         

                            Before

                     Selya, Circuit Judge,                                                     
                Coffin, Senior Circuit Judge,                                                        
                  and Stahl, Circuit Judge.                                                      

                                         

Brian  L. Lincicome with  whom Cozen  and O'Connor,  Ted Susi, and                                                                         
Laney and Susi were on brief for appellants.                      
Roy E.  Thompson, Jr. with whom  Elizabeth G. Knox  and Thompson &amp;                                                                              
Bowie were on brief for appellee.             

                                         

                      December 28, 1994
                                         

          STAHL,   Circuit   Judge.     Plaintiffs-appellants                      STAHL,   Circuit   Judge.                                              

William  and Rita Espeaignnette  brought this  action seeking

damages for  the loss of William  Espeaignnette's lower right

arm in  an accident involving a lumber-mill  saw designed and

manufactured  by defendant-appellee Gene  Tierney, Inc. ("the

Company").   Following a four-day  trial, a  jury returned  a

special verdict in favor of the Company, specifically finding

that the  saw  was not  defectively designed.   The  district

court  entered  judgment  for  the  Company and  subsequently

denied   the   Espeaignnettes'  post-trial   motions.     The

Espeaignnettes now appeal, assigning  error to several of the

district court's  evidentiary rulings.  Because  we hold that

the  district  court  abused   its  discretion  in  excluding

evidence pertaining  to subsequent modifications made  to the

saw by Espeaignnette's1 employer,  we vacate the judgment and

remand for new trial.

                              I.                                          I.                                            

                          Background                                      Background                                                

          In  1990,  Espeaignnette's  employer, the  Isaacson

Lumber Company  ("Isaacson"), purchased  a Bottom  Arbor Gang

Saw, or  "edger," designed  and manufactured by  the Company.

Isaacson employs the edger to "square" or "edge" slabs of raw

lumber.   The edger operates in the following manner:  First,

                                                    

1.  All references  in the opinion  to "Espeaignnette"  refer
solely to William Espeaignnette.

                             -2-                                          2

the operator feeds slabs of raw lumber into the edger along a

roller table,  passing  the slabs  through anti-kick  fingers

that prevent the slabs from kicking back towards the operator

as  they contact the saw  blades.  After  passing through the

anti-kick fingers, powered infeed  rollers grab the slabs and

pull them into the saw blades.  As designed and manufactured,

the  area surrounding  the anti-kick  fingers and  the infeed

rollers is open and not guarded by any physical covering.

          The operator  controls  the edger  from  a  station

located  at one end of the machine.  During normal operation,

there is no need for the  operator to approach the open space

near the anti-kick fingers and  the infeed rollers, except to

inspect   or  listen   for  strips   of  "edged"   wood  that

occasionally "hang  up" in the  saw-blade area.   When strips

become stuck in this area, the operator must stop the machine

and clear the work surface or risk damaging the saw blades.

          Following    installation     of    the    machine,

Espeaignnette  was   trained  to   operate   the  edger   and

subsequently ran it without  incident for a period of  two to

three  weeks.  According  to his trial  testimony, on October

11, 1990, at approximately  10:30 p.m., Espeaignnette heard a

noise that he  thought indicated  that a sliver  of wood  had

become stuck in the saw-blade section of the edger.   At this

point, Espeaignnette had been working for sixteen hours, with

only a  half-hour lunch break.   Espeaignnette testified that

                             -3-                                          3

he walked to the side of the edger, crouched down, and peered

into the  blades  to investigate.   Espeaignnette  maintained

that  he did not stop the edger while investigating the noise

because  to  do   so  would  needlessly   increase  downtime,

explaining that the edger  often emitted similar sounds that,

upon investigation, did not require a shutdown.

          Espeaignnette  testified that while he was crouched

beside the  edger, he saw a sliver of wood work free from the

saw-blade area.  He then attempted to stand up but, as he did

so,  lost his  balance and  stumbled towards  the edger.   He

further testified that,  as he stumbled, he reached  out with

his right hand to balance himself and inadvertently stuck his

hand into the area  of the infeed rollers, causing  his right

glove to become caught on a roller.  As a result, his arm was

crushed,  pulled into  the saw-blade  area, and  then severed

below the right elbow.2

          Following  the accident, Isaacson  continued to use

the  edger  to cut  raw  lumber.    In the  summer  of  1993,

approximately six months before  trial, an Isaacson  employee

modified  the edger  by  welding to  it  a steel  plate  that

covered the open area by the infeed rollers and the anti-kick

fingers. 

                                                    

2.  The Company maintains that the accident  occurred because
Espeaignnette  purposely, and  not  inadvertently, stuck  his
hand into the area of  the infeed rollers to free a  piece of
wood.

                             -4-                                          4

          Espeaignnette tried this action against the Company

solely on  a theory  of strict liability,  alleging that  the

edger  was defectively  designed  and unreasonably  dangerous

because of  the lack of physical guards  covering the infeed-

roller  area.    As co-plaintiff,  Rita  Espeaignnette sought

compensation  for  loss  of   consortium  stemming  from  the

injuries to her husband.

          Prior  to trial,  the  Company moved  in limine  to                                                                     

exclude all evidence pertaining to Isaacson's modification of

the edger, and the  Espeaignnettes similarly moved to exclude

evidence  about the absence of comparable accidents involving

edgers  designed   by  the  Company.     The  district  court

provisionally granted  the Company's motion and  excluded the

modification  evidence pursuant  to Fed.  R. Evid.  407 as  a

subsequent  remedial   measure,  subject,  however,   to  the

condition  that  the  Company  not controvert  at  trial  the

feasibility   of   such   a   modification.3      The   court

                                                    

3.  Fed. R. Evid. 407 provides:

          When,  after an event, measures are taken
          which,  if  taken previously,  would have
          made  the  event  less  likely  to occur,
          evidence  of  the subsequent  measures is
          not  admissible  to  prove negligence  or
          culpable conduct in  connection with  the
          event.   This  rule does not  require the
          exclusion   of  evidence   of  subsequent
          measures   when   offered   for   another
          purpose,   such  as   proving  ownership,
          control, or  feasibility of precautionary
          measures,     if     controverted,     or
          impeachment.

                             -5-                                          5

provisionally  denied  the Espeaignnettes'  motion  and, over

objection, permitted the owner  of the Company, Gene Tierney,

to testify  about the absence  of reports of  other accidents

involving similar edgers designed by the Company.  

          During  trial, the  Espeaignnettes raised  at least

twice the issue of the subsequent-modification evidence.  The

district  court  declined  to  admit  the  evidence  on  each

occurrence.   Although eventually  finding that the  issue of

feasibility  had  been  clearly  raised,  the district  court

nonetheless excluded  the evidence pursuant to  Fed. R. Evid.

403 because the prejudicial impact of the evidence outweighed

its probative  value.4  The  Espeaignnettes made an  offer of

proof  stating,  inter alia,  that  they sought  to  call the                                       

current operator of the edger to testify that he had operated

the edger  both before and  after its  1993 modification  and

that  the modification had in  no way inhibited the operation

of the machine.

          During  trial, the  district court also  denied the

Espeaignnettes' objections  to the qualification of a witness

                                                    

4.  Fed. R. Evid. 403 provides:

          Although   relevant,   evidence  may   be
          excluded  if  its   probative  value   is
          substantially outweighed by the danger of
          unfair   prejudice,   confusion  of   the
          issues,  or  misleading the  jury,  or by
          considerations of undue  delay, waste  of
          time,   or   needless   presentation   of
          cumulative evidence.

                             -6-                                          6

for the Company  as an expert  in "industrial human  factors"

and  to that  witness's testimony  concerning whether  it was

possible for Espeaignnette  to have fallen into  the edger as

he alleged.

          Following  closing  arguments,  the district  court

submitted the case to the jury  as a series of questions on a

special-verdict  form.   The first  question was  whether the

edger  was  "in   a  defective  condition  and   unreasonably

dangerous."   The jury answered this question in the negative

and,  in accordance with the instructions on the form and the

district court's  oral  instructions, proceeded  no  further.

The jury did not answer the subsequent questions on proximate

cause  and assumption  of risk.   Subsequently,  the district

court  entered  judgment  for  the  Company  and  denied  the

Espeaignnettes' motions for judgment as a matter of law and a

new trial.  This appeal followed.

                             II.                                         II.                                            

                          Discussion                                      Discussion                                                

          The   Espeaignnettes   assign   error    to   three

evidentiary rulings.   They  contend that the  district court

erred  in (1)  excluding under  Rule 403  evidence concerning

Isaacson's  installation  of the  fixed  metal  guard on  the

edger, (2) admitting evidence concerning the absence of other

accidents involving  similar edgers designed  by the Company,

and (3) qualifying a witness for  the Company as an expert in

                             -7-                                          7

"industrial  human  factors" and  permitting  the  witness to

testify on that subject.  We discuss each argument in turn.

A.  Subsequent Modification of the Edger                                                    

          We  begin  by  noting  that a  district  court  has

considerable  latitude  in  determining whether  to  admit or

exclude evidence  under Rule 403.   See, e.g.,  Newell Puerto                                                                         

Rico,  Ltd. v.  Rubbermaid, Inc.,  20 F.3d  15, 21  (1st Cir.                                            

1994).   We  review  these  rulings  only  for  an  abuse  of

discretion.  Daigle v. Maine Medical Ctr., Inc., 14 F.3d 684,                                                           

690 (1st Cir. 1994).  "`Only rarely -- and in extraordinarily

compelling circumstances -- will we, from the vista of a cold

appellate  record,  reverse  a district  court's  on-the-spot

judgment concerning the relative  weighing of probative value

and unfair effect.'"   Id. (quoting Freeman  v. Package Mach.                                                                         

Co., 865 F.2d 1331, 1340 (1st Cir. 1988)).                 

          Our  review, however,  is  not  completely  without

bite.  See, e.g., Kassel v. Gannett Co., 875 F.2d 935, 951-52                                                   

(1st Cir. 1989).  In general, "[a]buse occurs when a material

factor  deserving significant  weight  is  ignored,  when  an

improper factor is  relied upon,  or when all  proper and  no

improper factors are assessed, but  the court makes a serious

mistake in  weighing them."  Independent Oil  &amp; Chem. Workers                                                                         

of  Quincy, Inc. v. Procter &amp;  Gamble Mfg. Co., 864 F.2d 927,                                                          

929 (1st Cir. 1988).

                             -8-                                          8

          The  Espeaignnettes argue  that the  district court

abused  its  discretion in  excluding  pursuant  to Rule  403

evidence  regarding  Isaacson's  modification of  the  edger.

Primarily, they contend  that the district  court incorrectly

found  that the  danger  of unfair  prejudice outweighed  the

probative value  of the  evidence.  The  Espeaignnettes argue

that the evidence was vital to establishing their prima facie

case  of  strict  liability  under  Maine  law and  that  the

district court  vastly  overestimated the  danger  of  unfair

prejudice.  After a careful review of both the applicable law

and  the facts  and circumstances  surrounding this  case, we

agree.5

          The  Espeaignnettes tried  their claim  against the

Company  pursuant   solely   to  Maine's   strict   liability

statute.6   Under the Maine  statute, a plaintiff  must prove

                                                    

5.  Because the district court excluded the evidence at trial
pursuant  to Rule  403,  its pre-trial  ruling excluding  the
evidence under Rule 407 as  a subsequent remedial measure  is
not  at issue.   Nevertheless, because  we are  remanding the
case  for retrial,  we  note that  circuit precedent  clearly
establishes  that Rule 407 does not apply to actions taken by
third parties such  as Isaacson.   Raymond v. Raymond  Corp.,                                                                        
938 F.2d 1518, 1524 (1st Cir. 1991).  

6.  The Maine strict liability statute provides:

          One who sells any  goods or products in a
          defective      condition     unreasonably
          dangerous to the  user or consumer or  to
          his property is subject to  liability for
          physical  harm thereby caused to a person
          whom the manufacturer, seller or supplier
          might  reasonably  have expected  to use,
          consume or  be affected by the  goods, or

                             -9-                                          9

that "the product  was defectively designed thereby  exposing

the  user to  an  unreasonable risk  of  harm."   Stanley  v.                                                                     

Schiavi Mobile Homes,  Inc., 462 A.2d 1144,  1148 (Me. 1983).                                       

See  also St. Germain v. Husqvarna Corp., 544 A.2d 1283, 1285                                                    

(Me. 1988).   To determine whether a  product was defectively

designed, Maine courts apply  the "danger-utility" test.  St.                                                                         

Germain,  544  A.2d  at 1285.    Under  this  test, proof  of                   

defective design  includes "an examination of  the utility of

[the  product's]  design,  the risk  of  the  design  and the

feasibility of  safer alternatives."7   Stanley, 462  A.2d at                                                           

                                                    

          to his property, if the seller is engaged
          in the business of selling such a product
          and it is expected  to and does reach the
          user  or   consumer  without  significant
          change  in the condition  in which  it is
          sold.  This  section applies although the
          seller has exercised all possible care in
          the preparation and  sale of his  product
          and the user  or consumer has  not bought
          the  product  from  or  entered  into any
          contractual relation with the seller.

Me. Rev. Stat. Ann. tit. 14,   221.

7.  In describing the feasibility prong of the danger-utility
test, a leading authority explains that:

          [a]n  alternative  design  that  was  not
          utilized is to be considered  as feasible
          when a reasonable  person would  conclude
          that the (1)  magnitude of the danger-in-
          fact that could have been avoided by such
          alternative design in the (2) utilization
          of the  scientific technological know-how
          reasonably  available  to  the  defendant
          outweighed  the  (1)  financial costs  of
          guarding  against such  avoidable danger,
          (2)  the impairment of  the benefits, and                                                          
          (3)  any  new  danger-in-fact that  would

                             -10-                                          10

1148.   See also Walker  v. General Elec. Co.,  968 F.2d 116,                                                         

119 (1st Cir. 1992).  

          In this case, the excluded evidence of the Isaacson

modification tends  to show that the  design and installation

of a  physical guard was  both possible and  practical (i.e.,

placing a physical guard over the opening did not inhibit the

operation  of  the edger).    Moreover,  this evidence  bears

directly on whether the edger  was defectively designed.   It

allows the jury to compare the utility and  risk of the edger

as actually designed (without the guard) with the utility and

risk  of the alternate  design (with the  guard).  Therefore,

because the evidence was crucial to the Espeaignnettes' case,

unless   the   danger  of   unfair   prejudice  substantially

outweighed its probative value,  the evidence should not have

been excluded.  See Swajian v. General Motors Corp., 916 F.2d                                                               

31, 34-35 (1st Cir. 1990) (reversing exclusion under Rule 403

in products liability action  where evidence bore directly on

event in issue); Laney v. Celotex Corp., 901 F.2d 1319, 1320-                                                   

21 (6th Cir. 1990) (reversing exclusion  under Rule 403 where

                                                    

          have  been  created  by  the  alternative
          design.

W. Page Keeton et al., Prosser and Keeton on the Law of Torts                                                                         
  99  at 700  (5th ed.  1984) (emphasis supplied).   Cf.  St.                                                                         
Germain,  544  A.2d at  1285-86  (evidence  "that the  safety                   
feature would minimally impair the  use of the saw" supported
determination   that  evidence  was   sufficient  to  find  a
defective condition  and that, consequently, the  trial court
had  erred in  directing verdict  for manufacturer  on strict
liability claim).

                             -11-                                          11

evidence "[went]  to the fundamental question  of the case").

Cf.  Joseph W. Cotchett &amp; Arnold B. Elkind, Federal Courtroom                                                                         

Evidence  93 (3d ed. 1993)  ("If the party's  case turns upon                    

the  introduction  of the  evidence,  [Rule  403] favors  the

admission of the evidence.").

          The   fact    that   the   court    permitted   the

Espeaignnettes'  expert  to  testify to  the  possibility  of

placing a physical guard  on the edger does not  diminish the

probative value  of the excluded  evidence.  The  Company did

not dispute the  fact that it  would have been  theoretically

possible to have installed a physical guard on the edger, but

it  did vigorously  dispute  whether such  a  guard would  be

practical.   The designer of the edger, Gene Tierney, and the

Company's expert witness, Professor Barnett, testified that a

physical guard  would unduly inhibit the  normal operation of

the edger.8   The  excluded evidence  tends to show  directly

                                                    

8.  Answering  why he chose  not to include  a physical guard
over  the  open area  of  the edger  where  Espeaignnette was
injured, Tierney testified:

          Utility of the  machine.   I have  found,
          almost without exception, that  where you
          have  a guard  bolted on,  hinged, pinned
          on,  even  clipped, they'll  take  it off
          first time  and it  stays off.   Then you
          have that whole opening exposed.

          Q.   You didn't  put a guard  because you
          were afraid someone would take it off?

          A.   I'm  saying you  use the  utility of
          that machine, how long do  you anticipate
          it  would  take  to take  the  guard  off

                             -12-                                          12

                                                    

          assuming  they  did put  it  back?   What
          would that --

          Q.  I'm sorry.  Go ahead.

          A.  What would that do to operator stress
          when  his material  is piling up  on him.
          That's going to make  him fight it, so to
          speak, to  catch up.  He's  more prone to
          error under those  conditions.  All those
          factors are considered.

Professor Barnett testified:

          The  methodology  of trying  to  get that
          thing unjammed is simply horrific, and we
          need every aperture available to us.
               . . . 
               Put  those guards  on  the side,  if                                                               
          they're permanently fixed  on there,  you                                                               
          have   now   seriously  compromised   the                                                               
          unjamming capability of  the machine.  If                                                          
          you  don't put them  on permanently, then
          the task  will be we have  to remove them
          so  we  can  get  in  there  and  do  the
          unjamming  on the  side.   If  you remove
          them, then  the machine is right  back to
          the one we're looking  at in the front of
          the room.

(Emphasis supplied).   In his opening  remarks, the Company's
counsel stated:

               One of the  reasons, you will learn,
          that there  is an  opening  in this  very
          area  is  it is  mandatory that  there be                                                               
          access    to    do    just   what    [the                            
          Espeaignnettes'  counsel] indicated,  and
          that is unjam, unplug  what can happen in
          there.   There is a necessity  to look in
          that  area and  to, once  the machine  is
          turned off, reach in and unplug it.

(Emphasis  supplied).    In addition,  the  Company's counsel
argued at closing:

          This machine  had to be  designed to keep
          this downtime to a minimum.

                             -13-                                          13

that a physical guard  does not inhibit the operation  of the

edger  and therefore  would  have rebutted  the testimony  of

Tierney  and Professor  Barnett  much more  effectively  than

hypothetical   assertions   by  the   Espeaignnettes'  expert

witness.

          Not only  did the district court  incorrectly gauge

the probative  value of the testimony,  it also overestimated

the  danger of unfair prejudice.  It is, of course, axiomatic

that "[a]ll  evidence is  meant to be  prejudicial; elsewise,

the proponent would  be unlikely  to offer it."   Daigle,  14                                                                    

F.3d at  690.    The  appropriate  inquiry  under  Rule  403,

therefore,  is   whether  the  evidence  results  in  "unfair

prejudice."    See  Swajian,  916  F.2d  at  34.     "`Unfair                                       

                                                    

               . . .
               And I  want you to think  just for a
          moment about some  testimony relative  to
          the jams  when the slab goes  in and gets
          really   hung   up   in  those   rollers.
          (Gesturing)  To get that slab out, you're
          going to have to go into the area between
          the  in-feed  rollers  and  the  kickback
          fingers.
               If you open up the machine and go in
          this way,  you're only getting one end of
          it.   You're not  getting the  major jam,
          which is where -- the in-feed rollers and
          the  antikickback fingers.    You had  to                                                               
          have access in that area.                                              

(Emphasis supplied).   Cf. Borden, Inc. v. Florida East Coast                                                                         
Ry. Co., 772 F.2d 750, 756 (11th Cir. 1985) ("[A] litigant is                   
unduly   prejudiced  when  his   opponent  is  successful  in
preventing  the  admission  of  evidence  on  a  particularly
crucial issue in dispute,  and then points to the  absence of
such evidence in closing argument.")

                             -14-                                          14

prejudice'  . . . means an undue tendency to suggest decision

on an  improper basis,  commonly, though not  necessarily, an

emotional one."  Fed R.  Evid. 403 advisory committee's note.

          In  its final  trial  ruling,  the  district  court

excluded the evidence, reasoning only that: 

          the prejudicial impact  of that  evidence
          as it relates  to Isaacson correcting the
          machine or having the  machine corrected,
          the prejudicial impact  of that  evidence
          outweighs  the  probative  value   of  it
          because the jury may very well infer from
          that activity  that that was  -- they may
          take   that   evidence  as   evidence  of
          negligence  or  product liability  on the
          part   of   the  defendant   rather  than
          evidence  for  which   it  is   intended;
          namely, the feasibility of   putting that
          or making that repair on the machine.

          The  district   court   viewed  the   evidence   as

admissible  (if at  all)  only to  show feasibility  under an

exception  to   Rule  407.     Therefore,  in   weighing  the

prejudicial  impact  of  the  evidence,  the  court  examined

whether  it  would  tend to  show  something  more  than just

feasibility  (e.g. negligence  or  product  liability).    As

noted, however, because  a third party, and not  the Company,

modified the edger, the evidence  of the modification was not

subject  to  exclusion under  Rule 407.    See supra  note 5.                                                                

Therefore,  the  fact  that  the   Espeaignnettes'  proffered

evidence  may  have tended  to  show  "negligence or  product

liability" rather  than just feasibility did  not, by itself,

                             -15-                                          15

constitute an improper  use of the  evidence and warrant  its

exclusion as unfairly prejudicial under Rule 403.  

          Moreover,  once the  analysis is  conducted outside

the Rule 407 framework,  we do not believe that  the excluded

evidence posed any significant risk of unfair prejudice.  The

Isaacson modification  was not a subsequent  design developed

well after the  edger was  manufactured.  Hence,  it was  not

(arguably) misleading or unfairly prejudicial on the issue of

whether the edger was  unreasonably dangerous at the time  of

manufacture.    See,  e.g.,  Grenada Steel  Indus.,  Inc.  v.                                                                     

Alabama Oxygen Co., 695 F.2d 883, 889 (5th Cir. 1983) (design                              

changes  developed after  the manufacture  of the  product in                              

question are  irrelevant to the reasonableness  of the design

at  the time of manufacture).  True, Isaacson did not install

a  guard on  the edger until  more than  two years  after the

accident.   The  Company, however,  does not  contend  that a

guard  could  not  have  been   installed  at  the  time   of

manufacture or even that the installation was not considered.

Therefore, the Espeaignnettes'  proffered evidence would  not

have introduced design  choices not known or feasible  at the

time of manufacture.

          Furthermore, the Company's failure in  its brief to

illustrate how  the  excluded evidence  would  be  "unfairly"

prejudicial to its case confirms our conclusion.  The Company

argues only that  the testimony would have been confusing and

                             -16-                                          16

misleading  to  the  jury  because  the  guard  installed  by

Isaacson  was a different  type of guard  (a permanent guard)

than the  guard recommended by the  Espeaignnettes' expert (a

removable guard).  Though this is a difference, we cannot say

that it is particularly confusing or unfairly prejudicial.

          In sum, the proffered evidence posed no significant

risk of unfair prejudice.9

          Nevertheless, we remain mindful of  the substantial

deference  that is  properly accorded  to a  district court's

judgment in "`steadying the  Rule 403 seesaw.'"   Kassel, 875                                                                    

F.2d at 952 (quoting Onujiogu, 817  F.2d at 6).  The question                                         

is not whether we would strike the balance differently in the

first instance, but whether the balance actually struck is so

egregiously  one-sided  that  it   requires  reversal.    Our

decision in Swajian v. General Motors Corp., 916 F.2d 31 (1st                                                       

Cir. 1990), in  which we reversed a district court's decision

                                                    

9.  We also note that in its provisional ruling before trial,
the  district court excluded the evidence under Rule 407, but
added, "I am more concerned, frankly, with prejudicial impact
that  that  kind   of  evidence  would  have   on  the  jury;
specifically, that  portion of  the evidence  which indicates
that  the  same  machine, at  the  same  place,  in the  same
factory,  was in  fact  remedied  to  prevent  this  kind  of
accident."    The  district  court  did  not  reiterate  this
reasoning when it excluded  the evidence under Rule 403.   In
any event, we are unconvinced that the fact that the evidence
concerned the specific edger  involved in the accident evokes
any special degree of unfair prejudice in this case.                                        

                             -17-                                          17

in a  products liability action to  exclude evidence pursuant

to Rule 403, informs our analysis on this issue.10  

          In Swajian, the plaintiff's  wife was killed when a                                

truck she  had been driving rolled over  in an accident.  The

plaintiff contended that the  truck's rear axle was defective

and had caused the accident.  General Motors argued, however,

that driver error was the cause.  The district court excluded

evidence  that the decedent  had been  drinking prior  to the

accident, finding that the evidence was "unduly inflammatory"

and  that  its  prejudicial  impact would  far  outweigh  its

probative value.  Id. at 34.                                   

          On  appeal, we  reversed, criticizing  the district

court for its  failure in  striking the Rule  403 balance  to

distinguish between evidence that is prejudicial and evidence

that  is  unfairly prejudicial.   Id.  at  35.   Moreover, we                                                 

stressed that  the evidence  was highly probative  because it

bore directly on the issue of causation.  Id.                                                         

          As  in  Swajian, the  evidence  excluded here  bore                                     

directly  on an  essential element  of the  plaintiff's prima

                                                    

10.  Even though  Swajian suggests that, there,  the district                                     
court  erred as  a  matter of  law by  not making  a specific
finding   of  "unfair   prejudice,"  the   opinion  is   best
interpreted  as holding  that the  district court  abused its
discretion  in  conducting   the  balancing  that  Rule   403
requires.   This  can  be deduced  from  the Swajian  panel's                                                                
review of  the district court's balancing  of probative value
against prejudicial  impact, Swajian, 916 F.2d  at 34, which,                                                
in turn, supports a conclusion that the district court abused
its discretion in striking the balance in this case.

                             -18-                                          18

facie case.  Furthermore, as compared to the circumstances of

this  case, we  think that  the risk  of unfair  prejudice in

Swajian was  decidedly more pronounced.   In Swajian,  a real                                                                

danger undoubtedly existed that the jury would have taken the

evidence of the  decedent's drinking as showing  that she was

at  fault and  not  entitled to  compensation, regardless  of

whether  or not  the axle  failure caused  the accident.   In

contrast, as  we have explained above,  the evidence excluded

in this case posed little, if any, risk of unfair prejudice.                                                             

          In sum, we are convinced that the excluded evidence

was  highly probative on an essential disputed element in the

case and  that the danger  of unfair prejudice  was extremely

remote.  Accordingly, we hold that the district court  abused

its discretion in excluding the proffered evidence.11

          Our  determination that  the district  court abused

its discretion  in striking  the Rule  403 balance does  not,

however, end our analysis.  As with most trial errors, we are

not  empowered   to  notice  error  in   a  district  court's

evidentiary ruling  "unless a substantial right  of the party

                                                    

11.  We  further note  that the  cases on  which  the Company
relies  to   support  excluding  the   evidence  are  clearly
distinguishable.  See Harrison v.  Sears, Roebuck &amp; Co.,  981                                                                   
F.2d 25,  31-32 (1st  Cir.  1992) (negligence  and breach  of
warranty action, evidence offered to  impeach only); Raymond,                                                                        
938  F.2d  at  1523-24  (feasibility  stipulated  and  design
modification developed after manufacture of product); Grenada                                                                         
Steel, 695 F.2d at  888-89 (feasibility clearly not contested                 
and  design  changes  developed  years  after  manufacture of
product).

                             -19-                                          19

is affected."  Fed. R. Evid. 103(a); see also Fed. R. Civ. P.                                                         

61.   In  determining whether  an  error affected  a  party's

substantial right,  "[t]he central question  is whether  this

court can say with fair assurance . . . that the judgment was

not substantially swayed  by the error."   Lubanski v. Coleco                                                                         

Indus.,  Inc., 929  F.2d  42, 46  (1st  Cir. 1991)  (internal                         

quotations omitted). 

          The exclusion of the proffered  testimony cannot be

considered  harmless.    As  noted,  the   evidence  directly

pertains to  whether the edger was  unreasonably dangerous at

the time of manufacture.   Therefore, we cannot say  that its

absence did  not substantially affect the  jury's decision on

this point.

          Furthermore, the only issue the jury considered was

whether the edger was unreasonably dangerous.  In accord with

the court's instructions, the  jury returned a single finding

that  the  edger  was  not  "in  a  defective  condition  and

unreasonably  dangerous."    The  jury  did  not  answer  the

subsequent questions on  the special-verdict form  concerning

proximate cause and assumption of risk.  As a result, because

the  exclusion of  the  evidence undermined  the jury's  sole

finding that the edger  was not in a defective  condition, it

therefore affected a substantial right of the Espeaignnettes.

B.  Absence of other accidents                                          

                             -20-                                          20

          The  Espeaignnettes contend that the district court

erred in  admitting evidence  concerning the lack  of similar

accidents  involving edgers  designed  by the  Company.   The

Espeaignnettes argue  that this  evidence is irrelevant  in a

strict  liability action  and, in  the alternative,  that the

Company  failed  to establish  a  proper  foundation for  the

evidence.  The Espeaignnettes fail on both grounds.

          As  an initial  matter, we  note that  both parties

argued this  issue before  the district  court  and in  their

briefs  as though it were  controlled by state  law.  Neither

side  discussed the  applicability  of the  Federal Rules  of

Evidence.  Nevertheless, it  is axiomatic that in determining

whether evidence  is relevant, and therefore  admissible in a                                         

diversity action,  the Federal  Rules of Evidence  supply the

appropriate rules of decision.  See, e.g., McInnis v. A.M.F.,                                                                         

Inc., 765 F.2d  240, 245-46  (1st Cir. 1985);  Fed. R.  Evid.                

1101.   Normally,  the Espeaignnettes'  failure to  argue the

correct  applicable standard  would  effect a  waiver of  the

issue.    Because we  are  remanding the  issue  for retrial,

however,  we will proceed to  discuss the issue  as it arises

under the Federal Rules of Evidence.  

          Subject  to  certain limitations,  all  evidence is

admissible if it is relevant -- i.e., if it tends to make the

existence or  nonexistence of a disputed  fact "more probable

than it would  be without the evidence."  Fed.  R. Evid. 401,

                             -21-                                          21

402.   As  we have  discussed earlier,  a district  court may

nonetheless exclude relevant evidence if the  probative value

of the evidence is "substantially outweighed by the danger of

unfair prejudice, confusion of  the issues, or misleading the

jury,  or by considerations of undue delay, waste of time, or

needless presentation of cumulative evidence."  Fed. R. Evid.

403.

          In general, courts have recognized that the absence

of prior accidents may be admissible to show:

          (1)   absence  of  the  defect  or  other
          condition alleged,
          (2) the  lack  of a  causal  relationship
          between  the injury  and  the  defect  or
          condition charged, [and]
          (3)   the   nonexistence  of   an  unduly
          dangerous situation.

Strong, 1 McCormick on  Evidence   200 at 850-51.   Moreover,                                            

we  recently rejected the argument that  evidence of the lack

of prior accidents is irrelevant on the issue of causation in

a  products liability  case brought  on a  negligence theory.

Harrison v. Sears,  Roebuck &amp; Co., 981 F.2d  25, 30 (1st Cir.                                             

1992).  See also  Keller v. United States, No.  94-1136, slip                                                     

op.  at 27, 30  (1st Cir. Oct. 19,  1994) (noting evidence of

the absence of other accidents as supporting district court's

failure  to find  design  defect or  causation in  negligence

case).12 

                                                    

12.  The  Espeaignnettes argue,  however,  that  even if  the
absence  of prior accidents would be relevant in a negligence
case,  the  district court  should  still  have excluded  the

                             -22-                                          22

          The evidence  of the absence of  prior accidents is

clearly  relevant to  several disputed  issues in  this case.

The  fact that the Company had received no reports of similar

accidents tends to  disprove causation.   That there were  no

similar reports  of injuries due to  inadvertent contact with

the infeed rollers tends  to support the Company's contention

that  it was not possible  for Espeaignnette to have stumbled

accidentally into the open  area of the edger as  he alleged.

Additionally, the absence of prior accidents is probative and

relevant to  whether the  edger as designed  was unreasonably

dangerous.

          The Espeaignnettes alternatively  contend that  the

Company  failed to  establish  the  necessary foundation  for

admission  of the evidence.   A review of  the cases reveals,

for  the most  part, that  evidence of  the absence  of prior

accidents may not be admitted unless the offering party first

establishes that  the  "lack of  accidents was  in regard  to

products that are substantially identical to the one at issue

and used in settings  and circumstances sufficiently  similar

to   those  surrounding  the  machine  at  the  time  of  the

                                                    

evidence because the issue here turns solely on principles of
strict liability.   This  argument is not  persuasive because
the  Maine  Supreme   Judicial  Court  has  recognized   that
negligence and  strict liability causes of  action both share
the same elements  of causation  and defective  design.   See                                                                         
Marois  v. Paper Converting Mach. Co., 539 A.2d 621, 623 (Me.                                                 
1988) (causation)  and Stanley,  462 A.2d at  1148 (defective                                          
design).    

                             -23-                                          23

accident."    Klonowski v.  International Armament  Corp., 17                                                                     

F.3d 992, 996 (7th  Cir. 1994) (internal quotations omitted).

Whether such preliminary requirements are aimed at preventing

the  admission  of   irrelevant  evidence  under   Rule  402,

excluding relevant  evidence that is unfairly prejudicial and

confusing under Rule 403, or both, is unclear.  Cf.  Fusco v.                                                                      

General Motors  Corp.,  11  F.3d 259,  264  (1st  Cir.  1993)                                 

(foundational requirement of substantial similarity regarding

evidence of  similar accidents "now loosely  appended to Rule

403").   In  any  event, the  determination of  admissibility

turns  on the  facts and  circumstances of  each case  and is

committed, in the first instance,  to the sound discretion of

the  district judge.  See  United States v.  Brandon, 17 F.3d                                                                

409, 444 (1st  Cir.), cert. denied, 115 S. Ct.  80, and cert.                                                                         

denied, 115 S. Ct. 81 (1994); Fed. R. Evid. 104(a).                  

          Prior  to  testifying  about  the  lack of  similar

accidents, Tierney  testified that, since  1976, his  company

had sold eighty-seven edgers  using essentially the same open

infeed-roller design.  He also testified that as president of

the Company any  claims or notices of accidents  involving an

edger  designed and  manufactured by  the Company  would have

come to his  attention.  While  in different circumstances  a

district   court  might  require   more  to  show  sufficient

similarity,  we think  that  Tierney's testimony  established

that  the  evidence of  the  absence of  other  accidents was

                             -24-                                          24

admissible  in  this case.    Furthermore, we  note  that the

Espeaignnettes'  counsel  soundly  attacked   this  testimony

during cross-examination,  bringing out that  Tierney did not

know whether any of the machines had been modified or if they

had been  situated so as  to prevent accidental  contact with

the infeed rollers. 

C.  Expert testimony                                

          The Espeaignnettes'  final  complaint is  that  the

district  court  improperly  permitted the  Company's  expert

witness to testify  that it was  not physically possible  for

Espeaignnette  to  stumble and  fall  into  the  edger as  he

contended.  Specifically, the Espeaignnettes contend that the

Company's  expert lacked sufficient qualifications to testify

as an  "industrial human  factors" expert in  machine design.

They further argue that  the subject of the testimony  -- how

one  reacts during a stumble  -- was an  improper subject for

expert testimony because it was  within the knowledge of  the

average juror.  We do not agree.

          Determinations of whether a witness is sufficiently

qualified  to testify  as an  expert on  a given  subject and

whether such expert  testimony would be helpful  to the trier

of  fact are committed to  the sound discretion  of the trial

court.   See, e.g., Navarro  de Cosme v.  Hospital Pavia, 922                                                                    

F.2d 926, 931 (1st Cir. 1991).  "[A] trial judge's rulings in

this  sphere should be upheld `unless manifestly erroneous.'"

                             -25-                                          25

United  States  v. Sepulveda,  15 F.3d  1161, 1183  (1st Cir.                                        

1993) (quoting Salem v. United States Lines Co., 370 U.S. 31,                                                           

35 (1962)), cert. denied, 114 S. Ct. 2714 (1994); but compare                                                                         

Williams v. Poulos, 11 F.3d 271, 282 (1st Cir. 1993) (stating                              

standard of review is abuse of discretion).  

          A review of Professor  Barnett's vita and testimony

reveals  that,  although  he   has  little  formal  education

regarding "industrial human factors," he  does have extensive

professional experience  in the field.  His testimony was not

restricted to how a  person reacts during a stumble.   Rather

he gave important testimony explaining human interaction with

machines, an issue both important in evaluating the Company's

decision  not  to place  a physical  guard  on the  edger and

relevant to the Company's theory  of causation.  The district

court did  not abuse its  discretion in either  accepting the

qualifications of Professor Barnett as an expert or admitting

his testimony.

                             III.                                         III.                                             

                          Conclusion                                      Conclusion                                                

          For the  foregoing reasons, we vacate  the judgment

entered  below and remand this case to the district court for

a new trial.

                             -26-                                          26
