### October 12, 2014



# D r af t
P R E S E N T A T I O N O F 

## E X P E R T 

## T E S T I M O N Y 

### P O L I C I E S 

### 1. Experts should be asked to identify and explain the theoretical and factual basis for any

conclusion and the reasoning on which the conclusion is based — and any

limitations of their conclusions. 2. Experts should present testimony in a manner that accurately and fairly convey s the significance of their conclusions, avoiding unexplained or undefined technical terms or words of art. 3. Experts should remain neutral, and attorney s should respect this neutrality

. 4. Experts should not testify bey o nd their expertise and should also appreciate the difference between testimony that the witness may

give as an expert and testimony

that the same witness may give as a lay

/fact witness. 1 

### 5. Experts should not testify on direct or redirect examination concerning case-specific conclusions not contained in the report(s)/documentation submitted in discovery

— unless in fair response to issues raised on cross-examination. I f an expert changes his or her opinion, a supplementary report should be submitted except where the change is occasioned by new information, presented during testimony and not previously

available to the witness. 6. Experts should not testify concerning conclusions that are bey ond the limits of a laboratory ’s testing protocols. 7. Experts should not use invalid or problematic terms in their reports or when testify

ing. 2

1 Th e sam e w itn ess m ay p ro v id e testim o ny

as b o t h anex p ert o r a layw itn ess. Th e tw o ro les n eed to b e d istin g u i sh ed . Th e Fed eral Ru les d o “ n o t d istin g u ish b etw eenex p ert an dlay w itn esses, b ut rath er b etw eenex p ert an dlay testim o ny . Certain ly

it is p o ssib le f

o r th e sam e w itn ess to p ro v id e b oth

lay an dexp ert testim o ny

ina sin g l e case.” F E D
. R. E V ID
. 7 0 1 ad v iso ry co m m ittee’ s n o te (2 0 0 0). 2 Fo r ex am

ple: “ to th e ex clu s io n

o f all o th ers” an d“ reaso n ab le scien tif ic certain ty .” Th ese term s are d iscu ssed b elo w . J urisd ictio n s th at req u ire th e p h rase “ reaso n ab le scien tif ic (o r m ed ical) certain ty ” sh o u ldreco n sid er its u se. 

### 1

### 8. Experts should not use misleading terms 3 

### that suggest that the

methodology

or the expert is infallible when testify ing. 4 

### 9. Experts should not use potentially misleading terms in their reports or when testify

ing without a clear explanation of the term’s significance and limitations. 5 

### 10. Experts should not use the term “scientific” when testify ing unless the basis for their opinions has been scientifically validated. 11. Trial judges should not declare a witness to be an expert in the presence of the jury

. 12. Attorney s have an obligation to understand the discipline — including its strengths and limitations — underly ing the expert testimony that is presented at trial and to appreciate the importance of consulting with experts prior to trial. 6 

### 13. The proponent of the expert testimony should not cause an expert to testify bey ond the opinion submitted in discovery or beyond the limits of the laboratory ’s testing protocols. 14. Attorney s should not mischaracteriz e expert evidence in their comments to the jury

.

3 Inth is co n tex t , “ m islead in g ” d oes n o t im p ly an inten t to m i slead ; th e ef

f ect o f th e testim o ny

o n th e j ury is th e f o cu s. In sh o rt, a j ury

canb e m isled

ev en in th e ab sen ce o f

an in ten t to m islead

. See F E D
. R

. E V I D
. 4 0 3 (“ m islead in g th e j ury ”); Daub ert v . Merrell Do w P h arm ., In c., 5 0 9 U.S. 5 7 9 , 5 9 5 (1 9 9 3 ) (“ Exp ert ev i d en ce can b e b o th p o w erf u l an dq u ite m islead in g b ecau se o f

th e d if f i cu lty in ev alu atin g it.”) (q u o tin gJ ack B. W ein stein , Ru le 7 0 2 o f th e Fed era l Ru les o f Eviden ce Is So u nd : It S h o u ld No t Be Amen d

ed , 1 3 8 F.R.D. 6 3 1, 6 3 2 (1 9 9 1 )); N A T I ONA L RE S E A RCH C O UNCI L , N A T I ONA L A CA DE MY OF S CI ENCE S , S T RE NG T HENI

NG F ORE

NSI C S CI EN CE I

N T HE UNI T E D S T A T E S : A P A T H F ORW A RD 4 (2 0 0 9 ) (“ im

precise o r ex ag g erated ex p ert testim ony h as so m etim es co n trib utedto th e ad m issio n o f erro n eo u s o r m islead in g ev id en ce”). 4 Fo r ex am

ple: “ zero erro r rate” an d“ 1 0 0 p ercen t accu rate.” See NAS F ORE NSI C S CI ENCE RE PORT , su

p ra n o te 3 , at 1 4 2

- 4 3 . Th ese term s are d iscu ssed b elo w . 5 Fo r ex am

ple: “ m atch ” an d“ co n sistent w ith .” Id

. at 2 1 . Th ese term s are d iscu ssed b elo w . 6 Th e Am erican Bar Asso ciatio n h as m ad e co m

p eten ce th e f

irst req u irem en t in

th e ru les o f p ro f essio n al co n du ct. S

ee ABA M ODE L R

ULE S OF P ROF ’ L C ONDUCT R. 1 .1 (a) (“ Co m p eten t rep resen tatio n

req u ires . . . th o ro u g h n ess an dp rep aratio n reaso n ab l y

n ecessary

f o r th e rep resen tatio n .”). Mo reo v er, th e Su p rem e Co urt h as d ecid edsev eral recen t cases o n th e Six th Am en d m en t rig ht to ef

f ectiv e assistan ce o f

co u n sel. S ee Hin to n v . Alab am a, 1 3 4 S. Ct. 1 0 8 1 (2 0 1 4 ) (f in din g co un sel in ef

f ectiv e f o r f ailin g to un d erstan d h o w

to retain a d ef

en s e ex p ert); Harrin g to n

v . Rich ter, 1 3 1 S. Ct. 7 7 0 , 7 8 8 (2 0 1 1 ) (“ Crim in al cases w ill arise w h ere th e o n ly reaso n ab le an dav ailab l e d ef en se strateg y

req u i res co n su l tatio n

w ith experts o r in t

ro du ctio n o f exp ert ev id en ce.”). 

### 2

### D I R E C T I V E 

### R E C O MM E N D A T I O N S 

### 1. The Attorney

General should direct federal prosecutors, forensic laboratories within the Department of J ustice, and laboratories under contract with the Department of Justice to follow the policies outlined above that are applicable to their duties. 2. The Attorney

General should request that the Organiz ation for Scientific Area Committees (OSAC) consider these policies in their best practices and standards development. 3. The Attorney

General should ask other jurisdictions to consider adopting the policies outlined above.

B A C K G R O U N D 

### The National Academy

of Sciences (NAS) report 7 

### on forensic science raised numerous issues about the presentation of expert testimony at trial, noting that “imprecise or exaggerated expert testimony has sometimes contributed to the admission of erroneous or misleading evidence.” 8 

### Such evidence undercuts the justification for expert testimony . I n Kumho Tire Company, Ltd. v. Carmichael , 9 

### the Supreme Court wrote: “ Daubert pointed out that Federal Rules 702 and 703 grant expert witnesses testimonial latitude unavailable to other witnesses on the ‘assumption that the expert’s opinion will have a reliable basis in the knowledge and experience of his discipline.’” 1 0 

### This memo identifies a number of problems that have arisen in the presentation of expert testimony in criminal prosecutions. 1 1

7 N A T I ONA L RE SE A RCH C OUNCIL , N A T I O N A L A CA DE M Y OF S CI EN CE S , S T RE NG T HENI

NG F ORE

N SI C S CI E

NCE I N T HE UN I T E D S T A T E S : A P A T H F O RW A RD (2 0 0 9 ) [h erein af

t er NAS F ORE

NSI C S CI ENCE R

E PORT ]. 8 Id

. at 4

. 9 5 2 6 U.S. 1 3 7 (1 99 9 ) (q u o tin g Da u bert an dp oin tin g o ut th at exp erts m ay

testif y to o p in io n s , in clu d in g th o se th at are n o t b asedo n f i rsth an d k n o w led g e o r o b serv atio n ). 10 Id

. at 1 4 7. 11 Th e co urts, h o w ev er, h av e n ot ap p lied Da u b ert rig o ro u sly incrim in al cases:
“ Th e b o tto m

lin e is sim

p le: In a n um

b er o f f o ren sic scien ce d i scip lin es, f o ren sic scien ce p ro f essio n als h av e y et to estab lish eith er th e v alid i ty

o f th eir ap p ro acho r th e accuracy o f th eir co n clu sio n s , an dth e co urts h av e b eenu tterly in ef f ectiv e inad d ressin g th is p ro b lem .” NAS F ORE NSI C S C IENCE RE PORT , su p r a n o t e 3 , at 5 3

. S

ee a lso id

. at 1 06 (“ Rev iew o f rep o rted j u d icial o p in io n s rev eals th at, at least in crim in al cases, f o ren sic scien ce ev id en ce is n o t ro utin ely scru tin izedp u

rsu an t to th e stan dard o f

reliab ility

en u n ciated in Da u b ert . . . . As th e rep o rted cases su g g est, h o w ev er, D a u b ert h as d o n e little to im p ro v e th e u se o f

f o ren sic scien ce ev id en ce in crim in al cases.”). 

### 3

### I. T E S T I F YI N G 

### B E Y O N D T H E 

### L I M I T S O F T HE 

### L A B O R A T O R Y 

### R E P O RT 

### State v. Troedel 1 2 

### illustrates this problem. Defendants Troedel and Hawkins were convicted of capital murder in separate trials. A report of a gunshot residue test using neutron activation analy sis concluded that swabs “from the hands of Troedel and Hawkins contained antimony and barium in amounts ty pically found on the hands of a person who has discharged a firearm or has had his hands in close proximity to a discharging firearm.” 1 3 

### The expert testified in accordance with this report at Hawkins’ trial but enhanced his testimony at Troedel’s trial, where he testified that “Troedel had fired the murder weapon.” 1 4 

### Troedel’s conviction was upheld by the state courts. During federal habeas proceedings, the expert’s deposition was taken, at which time he testified that “he could not, from the results of his tests, determine or say to a scientific certainty who had fired the murder weapon” and the “amount of barium and antimony on the hands of Troedel and Hawkins were basically insignificant.” 1 5 

### The district court found the trial testimony “at the very

least” misleading. The expert claimed that the prosecutor had “pushed” him further in Troedel’s trial, a claim that the prosecutor substantiated: “[ O] n e of the prosecutors testified [ at the habeas hearing] that, at Troedel’s trial, after [ the expert] had rendered his opinion which was contained in his written report, the prosecutor p ushed to ‘see if more could have been gotten out of this witness.’ W hen questioned why , in the Hawkins trial, he did not use [ the expert] opinion that Troedel had fired the weapon, the prosecutor responded he did not know why .” 1 6 

### I n granting habeas relief, the court observed:
I n light of this admission, the above testimony received at the evidentiary hearing and the inconsistent positions taken by the prosecution at Hawkins’ and Troedel’s trials, respectively , the Court concludes that the opinion Troedel had fired the weapon was known by the prosecution not to be based on the results of the neutron activation analy sis tests, or on any scientific certainty

or even probability . Thus, the subject testimony was not only misleading, but also was used by the State knowing it to be misleading. 1 7

12 Tro ed el v . W ainw rig h t, 6 67 F. Su

p p. 1 4 5 6 (S.D. Fla. 1 9 8 6 ), a ff’d , 8 2 8 F.2 d6 7 0 (1 1 th Cir. 1 9 8 7 ). 13 Id

. at 1 4 58

. 14 Id

. at 1 4 59

. 15 Id

. 16 Id

. at 1 4 59

. 17 Id

. at 1 4 59

- 6 0

. 

### 4

### (The court also found Troedel’s counsel ineffective. Because defense counsel

knew that the gunshot residue testimony was “critical,” his “failure either to depose the State’s expert witness or, more importantly, to consult with any other expert in the field, fell outside the scope of reasonably professional assistance.” 1 8 

### ) W itness Preparation As Troedel demonstrates, attorney s bear significant responsibility for the presentation of expert testimony . The adversary process requires attorney s to put forth their strongest case, a requirement that incents lawy ers to encourage their witnesses to testify in a way most favorable to their client’s position. 1 9 

### Sometimes the pressure is overt. 2 0 

### At other times it is subtle but nevertheless unmistakable. 2 1 

### The issue has arisen so often that the ABA Standards on Criminal Justice includes this provision: “A prosecutor who engages an expert for an opinion should respect the independence of the expert and should not seek to dictate the formation of the expert’s opinion on the subject.” 2 2 

### The commentary to the Standard reads: Statements made by phy sicians, psy chiatrists, and other experts about their experiences as witnesses in criminal cases indicate the need for circumspection on the part of prosecutors who engage experts. Nothing should be done by the prosecutor to cast suspicion on the process of justice

18 Id

. at 1 4 61

. 19 S

ee Mich ael J . Sak s, Accu ra cy v. Advo ca cy: Exp ert Testimo n y Befo re th e Ben ch , T E CH
. RE V . 4 3 , 4 4

- 4 5 (1 9 8 7) (“ [E]x p erts [are] v u ln erab le to th e p o ssib ly d isto rtin g in f

lu en ce o f law y ers. L o n g b ef

o re th e ex p ert an dlaw

y ers arriv e inco urt, a b o n dh as f o rm edb etw eenth em . Th e in f lu en ce o f th e law y er is co n sid erab le.”); J o h n I. Th o rn to n , Uses a n d

Ab u ses o f Fo ren sic S cien ce , 6 9 ABA J . 2 88 , 2 9 2 (1 98 3 ) (“ Th e ev id en ce w ill b e selected o r rej ectedw ith o n ly th o se item s th at co n f

o rm to th e arg u

m en ts o f o n e sid e actu ally

b ein g su bm ittedf o r ex am in atio n . A d istin ct p o ssib ility

ex ists th at th e resu lts o f

th e ex am in atio n

b y th e f o ren sic scien t ist w ill b e sk ew ed . . .. Th ese situ atio n s rep resen t p o ten tial so urces o f m isch ief . . .. Th e d an g er is th at co n f licts easily arise b etw eenscien tist an dlaw y er — th e f

o rm er attem

p ts to d escrib e th e ev id en ce as it actu ally is, w h ile th e latter attem

p t s to d escrib e it inth e m o st f av o rab le lig h t.”). 20 S

ee Ban k o f No v a Sco tia v . Un itedStates, 4 87 U.S. 2 5 0 , 2 5 8 (1 9 8 8 ) (statin gth at th e “ District Co urt f

urth er co n clu d edth at o n e o f th e p ro secuto rs im

p ro p erly arg u edw ith

an exp ert w itn ess durin g a recess o f th e g ran dj ury

af ter th e w itn ess g av e testim o ny ad v erse to th e g o v ern m en t ”); Fly

nn McRo b erts & Stev e Mills, Fro m th e S ta rt, A Fa u lt S cien ce: Testimo n

y o n Bite Ma rks Pro n e to Erro r , C HI
. T RIB ., Oct. 1 9 , 2 0 0 4 (“ Yo u g et p u sh eda little b it b y

p ro secuto rs, an dso m etim es y o u

say OK to g et th em

to shut u p . . . . ‘ I allo w edm

y s elf to b e p u s h ed .’ ”) (q u o tin g a f o ren sic d en tist).

21 S

ee B A RRY S CHE CK

E T A L ., A CT UA L I NNOCE NCE : F IV E D AY S T O E X E CUT I ON A ND O T HE R D I SPA T C HE S F ROM T HE W RONG L Y C ONV I CT E D 3 1 (2 00 0) (“ Ask edlater if h e w as p ressured to ch an g e h is f

in d in g s o n

Co ak ley , [Dr.] Sh aler [th e ex p ert] said n o . ‘ Mo st atto rn ey s,’ Sh aler w o u ldalso say , ‘ lik e to let y o u k n ow w h at th eir o p i n io n s o f

th e f acts o f th e case are — irresp ectiv e o f th e scien tif

ic co n clu sio n s.’ ”). 22 ABA S T A

NDA RDS ON C RIMI

N A L J UST I CE , P ROSE CUT I ON A ND D E F ENSE F UNCT I ON , Stan d ard 3

- 3 .3 (a) (3 ded . 1 9 9 3 ). 

### 5

### by suggesting that the expert color an opinion to favor the interests of the prosecutor. 2 3 

### A comparable standard applies to defense counsel — and for the same reasons. 2 4 

### * * * I n sum, experts should not testify bey ond the opinions expressed in their laboratory

reports. I f an expert changes her opinion, a supplementary report should be written and disclosed. This is consistent with the “continuing duty to disclose” (which is found in pretrial discovery rules) and is intended to prevent trial by ambush. Such a requirement also provides experts with some protection from overreaching by

litigators.
II. T E S T I F YI N G 

### B E Y O N D T H E 

### L I M I T S O F 

### L A B O R A T O R Y 

### P R O T O C O L S 

### I nconsistent testimony

concerning the same technique probably occurs because experts do not follow laboratory protocols when testify

ing and because their testimony

is not monitored by

the laboratory

. 2 5 

### This was a major problem in the bullet lead cases. Comparative analy sis of bullet lead compared trace chemicals found in bullets at crime scenes with ammunition found in the possession of a suspect. 2 6 

### For over thirty y ears experts testified about bullet lead composition, a technique that was first used in the investigation into President Kennedy ’ s assassination. The published cases reveal a wide variety of interpretive conclusions. I n some cases, experts testified only that two exhibits were “analy tically indistinguishable.” 2 7 

### I n

other cases, experts concluded that samples c ould have come from the same “source” or “batch.” 2 8 

### I n still other cases, experts stated that the samples camefrom the same source. 2 9 

### The testimony in a number of cases went further and referred to a “box” of ammunition (usually fifty loaded

23 Id

. cm

t. at 5 9

. 24 Id

. Stan d ard4

- 4 .4 (a). 25 Th e lack

o f a p ro to co l co u ldalso cau se in co n sistent testim o ny . 26 Vario u s an aly

tical tech n iq u es (e.g ., n eu tro n activ atio n

an aly sis, in du ctiv ely co u pledp lasm a- ato m ic em issio n sp ectro m etry ) h av e b een u sedto d eterm in e th e co n cen tratio n s o f sev en elem ents — arsen ic, an tim o ny , tin , co p p er, b ism ut h , silv er, an dcad m ium

— inth e b u llet leadallo y o f b o th th e crim e- scen e an dsu sp ect’ s b u llets. Statistical tests are th en u s edto co m

p are th e elem en ts in

each b u llet. 27 W ilk erso n

v . State, 7 7 6 A.2 d6 8 5 , 6 8 9 (Md . Ct. Sp ec. Ap p. 2 0 0 1 ). 28 State v . Kru m

m ach er, 5 2 3 P .2 d 1 0 0 9 , 1 0 1 2- 1 3 (Or. 1 9 7 4 ) (en b an c). 29 Un itedStates v . Dav is, 1 0 3 F.3 d6 6 0 , 6 7 3- 7 4 (8 th Cir. 1 9 9 6 ); P eo p le v . L an e, 6 2 8 N.E.2 d6 8 2 , 6 89

- 9 0 (Ill. Ap p . Ct. 1 9 9 3 ) (“ He testif iedth at th e tw o b u llets w ere an aly tically in d istin g u ish ab le. Sp ecial Ag en t Riley o p in edth at th e tw o b u llets cam e f ro m th e sam e so urce an d th at th e m atchw as as g o o das h e h adev er seen inh i s tw en t y y ears w ith

th e FBI.”). 

### 6

### cartridges, sometimes twenty ). For example, two specimens:

• Could have come from the same box, 3 0



### • Could have come from the same box or a box manufactured on the same day , 3 1



### • W ere consistent with their having come from the same box of ammunition, 3 2



### • Probably

came from the same box, 3 3



### • Must have come from the same box or from another box that would have been made by

the same company

on the same day

. 3 4 

### Several other (and different) statements appear in the opinions. An early case reported that the specimens “had come from the same batch of ammunition: they had been made by

the same manufacturer on the same day and at the same hour .” 3 5 

### One case reports the expert’s conclusion with a statistic. 3 6 

### I n another case, the expert used the expressions “rare finding” 3 7 

### and “a very

rare finding.” 3 8 

### I n still another case, the expert “opined that the same company produced the bullets at the same time, using the same lead source. Based upon Department of J ustice records, she opined that an overseas company called PMC produced the bullets around 1982.” 3 9


### I n later y ears, the testimony became more limited. A 2002 publication states the conclusion as follows: “Therefore, they likely originated from the same

30 State v . Strain , 8 8 5 P .2 d 8 1 0 , 8 1 7 (Utah Ct. Ap p. 1 99 4 ); State v . J on es, 4 2 5 N.E.2 d1 2 8 , 1 3 1 (In d . 1 9 8 1 ).

31 State v . Gru

b e, 8 8 3 P .2 d1 0 6 9 , 1 0 7 8 (Id ah o 1 9 9 4); P eo p le v . J o h n so n , 4 99 N.E.2 d1 3 5 5 , 1 3 6 6 (Ill. 1 9 8 6 ); State v . Earh art, 8 2 3 S.W .2 d6 0 7 , 6 1 4 (Tex . Crim . Ap p . 1 9 9 1 ) (en b an c) (“ He later m o d if

iedth at statem en t to ackn o w led g e th at an aly tically in d istin g u ish ab le b u llets w h ichd o n o t co m e f

ro m th e sam e b o x m ost lik ely w o u ldh av e b eenm anu f

actured at th e sam e p lace o n o r ab o ut th e sam e d ay ; th at is, inth e sam e b atch .”), va ca ted , 5 09 U.S. 5 1 7 (1 99 3 ). 32 State v . Rey

n o ld s, 2 9 7 S.E.2 d5 3 2 , 5 3 4 (N.C. 1 9 8 2 ). 33 Bry an

v . Ok lah om a, 9 3 5 P .2 d3 3 8 , 3 6 0 (Ok l a. Crim . Ap p . 1 9 9 7 ). 34 Un itedStates v . Dav is, 1 0 3 F.3 d6 6 0 , 6 6 6- 6 7 (8 th Cir. 1 9 9 6 ) (“ An

expert testif iedth at su cha f

i n d in g is rare an dth at th e b u llets m u st h av e co m e f

ro m th e sam e b o x o r f

ro m an o t h er b o x th at w o u ldh av e b eenm ad e b y th e sam e co m

p an y o n th e sam e d ay .”); Co m

m o nw ealth v . Day e, 5 8 7 N.E.2 d1 94 , 2 0 7 (Mass. 1 99 2 ); State v . Kin g , 5 4 6 S.E.2 d5 7 5 , 5 8 4 (N.C. 2 0 0 1 ) (Th e exp ert “ op in edth at, b asedo n h er lead an aly sis, th e b u llets sh e ex am in edeith er cam e f ro m th e sam e b o x o f

cartrid g es o r cam e f

ro m d if f eren t b o x es o f

th e sam e calib er, m anu f

acturedat th e sam e tim e.”). 35 Bro w

n v . State, 6 0 1 P .2 d 2 2 1 , 2 24 (Alask a 1 97 9 ) (em p h asis ad ded ). 36 State v . Earh art, 8 2 3 S.W .2 d6 07 , 6 1 4 (Tex . Crim . Ap p . 1 9 9 1). 37 Un itedStates v . Dav is, 1 0 3 F.3 d6 6 0 , 6 6 6 (8 t h Cir. 1 9 96 ). 38 Id

. at 6 6 7. 39 P eo p le v . Villarta, No . H0 2 13 5 4, 2 00 2 Cal. Ap p . Unp u b . L ex i s 4 7 76 , at * 1 5 (Cal. Ct. Ap p . J an . 1 7 , 2 0 0 2). 

### 7

### manufacturer’s source (melt) of lead.” 4 0 

### Testimony

to the same effect was also proffered: “W ell, bullets that are analy tically indistinguishable likely

come from the same molten lead sources of lead, uh, as opposed to bullets that have different composition come from different, uh, melts of lead.” 4 1 

### A 2004 NAS report undercut this testimony , finding that the amount of bullets that can be produced from a melt “can range from the equivalent of as few as 12,000 to as many

as 35 million 40grain, .22 caliber longrifle bullets.” 4 2 

### Based on this finding, the report concluded: “The available data do not support any statement that a crime bullet came from a particular box of ammunition. I n particular, references to ‘boxes’ of ammunition in any form should be avoided as misleading under Federal Rule of Evidence 403.” 4 3


### III. W I T H H O L D I N G 

### I N F O R M A T I O N A T 

### T R

I A L 

### I n Driscoll v. Delo , 4 4 

### a capital murder case, the laboratory report indicated that blood traces on Driscoll’s knife were ty pe A, which matched the blood of a prison guard who had been injured by a stab wound but did not match the blood ty pe of a murdered guard whose blood ty p e was O. To explain the absence of ty pe O blood, the prosecution offered several theories, one of which was that the presence of the ty

pe O blood was “masked” by the ty pe A blood. The chief serologist of the state crime laboratory testified about this theory at trial. Only

in a subsequent habeas proceeding was it revealed that the serologist had performed another test, which had eliminated the “masking” problem, revealing the lack of ty pe O blood. “The jury was never informed that the lattes test was performed or that no ty pe O blood was on the knife . . .. I n its closing argument, the state made much of the masking theory , turning unfavorable serology evidence into neutral evidence at worst.” 4 5

40 Ch arles A. P eters, Th e Ba sis fo r Co mp o s itio n a l Bu llet Lea d Co mp a riso n s , 4 F ORE NSI C S C I
. C OMMUNI CA T I ONS No . 3 , at 5 (J u l y 2 00 2 ) (em

p h asis ad d ed ). 41 Tran scrip t

o f Trial Testim o ny

o f Ch arles P eters, Co m

m onw ealthv . W ilco x , Ken tu ck y , Feb . 2 8 , 2 0 02

. 42 Id

. 43 N A T I ONA L RE SE A RCH C OUNCIL , N A T I O N A L A CA DE M Y OF S CI EN CE S , F ORE NSI C ANA L YSI S : W E I G HI

NG B ULL

E T L E AD E V I DENCE 6 (2 0 0 4 ). 44 7 1 F.3 d 7 0 1 , 7 0 7 (8 th Cir. 1 9 9 5 ). Th e ef

f ectiv e assistan ce o f

co un sel w as also raised : W h eth er alleg edm urd er w eap o n

“ h adb lo o dm atch in gth e v i ctim ’ s co n stitu t edanissu e o f th e u tm o st im

po rtan ce. Un d er th ese circu m stan ces, a reaso n ab le d ef en se law y er w o u ldtak e so m e m easures to un d erstan dth e lab o rato ry tests p erf o rm edan dth e in f

eren ces th at o n e co u ldlo g ically d raw f ro m th e resu lts. At th e v ery

least, an y

reaso n ab le atto rn ey

un d er th e circu m stan ces w o u ld stu d y th e state’ s lab o rato ry

rep o rt w ith

su f f i cien t care so th at if

th e p ro secutio n

ad v an ced a th eo ry at trial th at w as at o dd s w ith th e sero lo g y

ev id en ce, th e d ef

en se w o u ldb e ina p o sitio n to ex po se it o n cro ss- ex am in atio n .” Id

. at 7 0 9

.

45 Id

. at 7 0 8. 

### 8

### I n the Cruz and Hernandezprosecutions, the misuse of scientific evidence

as well as other evidence led a police officer and an Assistant Attorney General to resign in protest during the initial proceedings and eventually lead to trials of the original prosecutors and police officers. 4 6 

### For example: W hen a crime technician arrived at the courthouse to testify for the state, he pulled aside one of the prosecutors and relay ed some news: representatives from the Nike shoe company said that the prints at the back window had been made by a woman’s shoe, perhaps siz e six or five and a half. Either siz e was too small for Cruz or Hernandez . The prosecutor put the technician on the witness stand and carefully avoided any

mention of the shoe siz e or likely

gender. I

n fact, the defense was not told about the Nike analy sis. 4 7 

### The defendants were later exonerated by DNA analy sis. 4 8


### I n Mitchell v. Gibson , 4 9 

### an expert provided the jury with evidence implicating the accused in an sexual assault, which — based on evidence withheld from the defense — the expert knew was misleading. The Tenth Circuit observed that this improper conduct was compounded by “the prosecutor, whom the district court found had ‘labored extensively at trial to obscure the true DNA test results and to highlight [ the expert’s] test results,’ and whose characteriz ation of the FBI report in his closing argument was ‘entirely unsupported by

evidence and . . . misleading.’” 5 0

46 S

ee Barry Sieg el, Presu med

Gu ilty; An Illin o is Mu rd er Ca se Beco mes a Test o f Co n scien ce In sid

e th e S ystem , L .A. T I ME S , No v . 1 , 1 99 2, (Mag azin e) at 1 8 (q u o tin gf orm er d etectiv e J o h n

Sam ); Bran d o n

L . Garrett, C ONV I CT I NG T HE I NNOCE

NT : W HE RE C RIMI

NA L P ROSE CUT I ONS G O W RONG (2 0 1 1 ) (d iscu ssin gcase)..

47 S CHE CK

E T A L ., su p ra n o te 2 1 , at 1 78

. 48 E DWA RD C ONNORS E T A L ., N A T ’ L I NST
. OF J UST I CE , C ONV I C T E D BY J URI E S , E X ONE RA T E D BY S CI ENCE : C A SE S T UDI E S I N T HE U SE OF DNA E V I DENCE T O E ST A BLI SH I NNOCE NCE A F T E R T RI

A L 4 4 (1 99 6 ) (d iscu ssin g cases o f Ro lan d o Cru z an dAlej an d ro Hern an d ez) [h erein af ter Ex o n erated b y

Scien ce]. S

ee a lso Bran d o n

L . Garrett & P eter J . Neu f eld , In va lid Fo ren sic S

cien ce Testimo n

y a n d W ro n g fu l Co n victio n s , 9 5 V A
. L

. RE V
. 1 (2 0 0 9) (Th e stu dy id en tif iedsev eral d if

f eren t ty pes o f in v alidtestim ony : (1 ) p resen tin gn on - p ro b ativ e ev i d en ce as p ro b ativ e, (2 ) d isco u

n t in g ex cu l p ato ry

ev id en ce, (3 ) u s in g in accu rate f req u en cies o r statistics, (4 ) p ro v id in g a statistic w i th out su p p o rt, (5 ) p ro v id i n g n o n - n um erical statem en ts w ith o ut em p i rical su pp o rt, an d(6 ) attrib utin g th e so u rce o f ev id en ce to th e d ef

en d an t.). 49 2 6 2 F.3 d1 0 3 6 (1 0 th Cir. 2 0 0 1 ). “ Th e resu l t

s th us co mp letely u n d

ermin ed Ms. Gilch rist’s testimo n

y. ” Id . at 1 0 64 (em

p h asis in o rig i n al) (“ An

ex p ert testif

iedat th e ev id en tiary h earin g th at th e DNA testin g p erf o rm edb y Ag en t Vick

un q u estio n ab ly

elim in ated

Mr. Mitch ell . . . . Th is exp ert rev iew edMs. Gilch rist’ s trial testim o n y . . . an dstated

th at th e testim o ny

w as b ased o n th e u se o f

test m eth o d s Ms. Gilch rist k n ew w ere less p recise th an

th e DNA tests w

h ich elim in atedMr. Mitch ell. Mo reo v er, h e p o in tedo ut th at o n e o f th e tests sh e p erf

o rm edinf

act ex clu d edMr. Mitch ell.”).

50 Id

. 

### 9

### I n the North Carolina I nnocence I

nquiry Commission’s investigation into the Greg Tay

lor case, the bench notes of the serologist, who had examined evidence for Tay

lor’s original trial, surfaced. The lab report noted that there were “chemical indications for the presence of blood.” 5 1 

### I n contrast, the bench notes showed that a subsequent confirmatory test was negative. These results were not disclosed to the prosecution or the defense at trial. As a result of this disclosure, the State Attorney

General commissioned an investigation into the lab’s practices, which was conducted by

two former FBI

officials. They

concluded: This report raises serious issues about laboratory reporting practices from 1987-2003 and the potential that information that was material and even favorable to the defense of criminal charges filed was withheld or misrepresented. The factors that contributed to these issues range from poorly

crafted policy ; lack of objectivity [ ;] the absence of clear report writing guidance; inattention to reporting methods that left too much discretion to the individual Analy st[ ;] lack of transparency ; and ineffective management and oversight of the Forensic Biology Section from 1987 through 2003. 5 2


### I n particular, the investigation identified four different ty pes of improper reporting. These included reports that: (1) mentioned that tests for the presence of blood are not conclusive but fail to report a confirmatory negative test; (2) failed to mention one or more negative or inconclusive confirmatory tests; (3) stated that no further tests were conducted when, in fact, one or more confirmatory

tests were conducted with negative or inconclusive results; and (4) overstated laboratory

test results or where lab notes contradicted reported result. 5 3


### IV. O VE R S T A T E M E N T S I N 

### T E S T I M O N Y 

### Cases in which expert testimony goes beyond the limitations of a scientific technique are not uncommon. 5 4 

### For example, hair evidence has frequently been

51 Mik e Klin k o su

m , State v . Tay lo r a n d

th e No rth Ca ro lin a S ta te Bu rea u o f In vestig a tio n La b S

ca n d a l , C HA MPI ON 1 0 (May

2 0 1 1 ). 52 C HRI S S W E C K E R & M I CHA E L W OL F , AN I NDE PENDENT R E V I E W OF T H E SBI F ORE NSI C L A BORA T O RY 4 (2 0 1 0 ), av ailab le at h ttp ://w w w .n cid s .co m

/f o ren s ic/sb i/Sw eck er_ Rep o rt.p d f

. 53 Id

. at 3

. 54 S

ee State v . Sp en cer, 2 1 6 N.W .2 d1 31 , 1 3 4 (Min n . 1 9 7 4 ) (“ W e are co n cern ed

. . . ab o ut th e sw eep in g an dun q u alif iedm an n er in w h i ch[th e ex p ert’ s] testim o ny w as o f f ered

. . . . An exp ert w itn ess co u ldb e p erm ittedto testif y th at inh is o p in io n

th e ch em icals p resen t o n d ef en dan t’ s h an d m ay

h av e resu l tedf

ro m th e f irin go f a g un . He sh o u ldn ot h av e b eenp erm ittedto state, as h e d id , th at th is d ef en d an t h add ef in itely f ired a g un .”); Den n is S. Karj ala, Th e Eviden tia ry Uses o f Neu tro n Activa tio n An a lysis , 5 9 C A L
. L

. RE V . 9 9 7 , 1 0 2 4 (1 9 7 1 ) (“ [F]ew experts h av e u sed ap pro p riate care in lim itin g th eir testim o ny .”). 

### 10

### misused. 5 5 

### I n one case, the expert testified that the crime scene hair sample “was

unlikely to match anyone ” other than the defendant, Edward Honaker. 5 6 

### At best, the expert could have testified that the hairs were “consistent,” which means that they could have come from Honaker or thousands of other people. 5 7 

### Honaker was later exonerated by

DNA testing. Similarly , in W

illiamson v. Reynolds , 5 8 

### the expert testified that hair samples were “consistent microscopically ” 5 9 

### and then went on to explain what this meant: “In other words, hairs are not an absolute identification, but they either came from this individual or there is — could be another individual somewhere in the world that would have the same characteristics to their hair.” 6 0 

### Five day s before W illiamson’s scheduled execution for murder, a federal judge granted his petition for habeas relief. He was later exonerated by DNA testing. 6 1


### V. T E S T I F YI N G 

### B E Y O N D 

### E XP E RT I S E 

### ; L A Y 

### T E S T I M O N Y 

### An expert’s testimony

must relate to the subject matter on which the expert has been qualified. “I t goes without saying that an expert qualified to testify upon one topic may

be completely

unqualified to testify about another as to which he lacks special knowledge, skill, experience, or training, but some applications of this principle take the unwary by surprise.” 6 2 

### I n People v. Ayala , 6 3 

### an expert recogniz ed this limitation: “Dr. Kellerhouse acknowledged that he was not a ballistics expert, and declined to testify about the bullets’ caliber .... As a radiologist, Dr. Kellerhouse could testify that the bullets were located so that their relative siz e would not be distorted in the X-ray photographs.” 6 4

55 “ Six t

y - f iv e o f th e trials ex am in edin v o lv edm icro sco pic h air co m p ariso n an aly sis. Of

th o se, 2 5 — o r 3 8 % — h adin v alidh air co m p ariso n testim o ny . Mo st (1 8 ) o f

th ese cases in v olv edin v alidin d iv idu alizin g claim s.” Bran d o n L . Garrett & P eter J . Neu f eld , In va lid Fo ren sic S

cien ce Testimo n

y a n d W ro n g fu l Co n victio n s , 9 5 V A
. L

. RE V
. 1 , 4 7 (2 00 9). 56 E X ONE RA T E D BY S CI ENCE , su pra n ote 4 8 , at 6 5 (em

p h asis ad d ed ). 57 S

ee B.D. Gau dette, Pro b a b ilities a nd Hu ma n Pu b ic Ha ir Co mp a riso n s, 2 1 J

. F ORE NSI C S C I
. 5 1 4 , 5 1 4 (1 97 6 ) (“ If a p u b ic h air f ro m th e scen e o f

a crim e is f

o un dto b e sim ilar to th o se f ro m a kn o w n so u rce, [th e co urts] d o n o t k

n o w w h eth er th e ch an ces th at it co u ldh av e o rig in atedf

ro m an o t h er so urce are o n e intw o o r o n e ina b illio n .”). 58 9 0 4 F. Su

p p. 1 52 9 , 1 5 5 8 (E.D. Ok l. 1 9 9 5 ), a ff’d , 1 1 0 F.3 d1 5 0 8 , 1 5 23 (1 0 th Cir. 1 9 9 7 ). 59 Id

. at 1 5 54

.

60 Id

. (em

ph asis ad d ed ). 61 S

ee J OHN G RI SHA M , T HE I N N OCE NT M A N : M URDE R A

ND I NJUST I CE I

N A S MA LL T OW N (2 0 0 6) (d iscu ssin g W illiam so n case). 62 J OHN M A G

UI RE , E V I DENCE : C OMMON S ENSE A N D C OMMON L A W 3 0- 3 1 (1 9 4 7 ). 63 6 P .3 d1 9 3 (Cal. 2 0 0 0 ). 64 Id

. at 2 1 5. 

### 11

### Further, a witness may be an expert on one aspect of a technique but not on other aspects. Accordingly , courts must “differentiate between ability to operate an instrument or perform a test and the ability to make an interpretation drawn from use of the instrument.” 6 5 

### For example, a police officer may be qualified to conduct a horiz ontal gaz e ny stagmus test (an intoxication test) but not be qualified to interpret the results. [ The officer’s] opinion that appellant was under the influence of alcohol, to the extent it was based on the ny stagmus test, rests on scientific principles well beyond his knowledge, training, or education. W ithout some understanding of the processes by which alcohol ingestion produces [ ey e] ny stagmus, how strong the correlation is, how other possible causes might be masked, what margin of error has been shown in statistical survey s, and a host of other relevant factors, [ the officer’s] opinion on causation, notwithstanding his ability to recogniz e the sy mptom, was unfounded. 6 6 

### Moreover, a witness may testify as both a lay (fact) witness and an expert witness — e.g., a pathologist performing an autopsy

. 6 7 

### The Federal Rules do “not distinguish between expert and lay witnesses , but rather between expert and lay testimony

. Certainly

it is possible for the same witness to provide both lay and expert testimony

in a single case.” 6 8 

### Attorney s and experts should appreciate the difference.
VI. M I S L E AD I N G 

### T E R M S I N 

### T E S T I M O N Y 

### As noted above, the NAS report on forensic science raised numerous issues about the presentation of expert testimony at trial, noting that “imprecise or exaggerated expert testimony has sometimes contributed to the admission of erroneous or misleading evidence.” 6 9 

### The report later voiced concern about the use of terms such as “match,” “consistent with,” “identical,” “similar in all respects tested,” and “cannot be excluded as the source of.” These terms can have “a profound effect on how the trier of fact in a criminal or civil matter perceives and evaluates scientific evidence.” 7 0

65 P eo p le v . Kin g , 7 2 Cal. Rp tr. 4 7 8 , 4 9 1 (Cal. Ct. Ap p. 1 96 8 ). 66 P eo p le v . W illiam s, 5 Cal. Rp tr. 2 d1 3 0 , 1 3 5 (Cal. Ct. Ap p. 1 9 9 2 ). 67 Testim o ny

th at in v o lv es th e o b serv atio n o f w o un d s o n

a d eced en t is lay testim o ny , w

h i le th e in terp retatio n

o f th o se w o un ds inv o lv es ex pertise. 68 Fed . R. 7 0 1 ad v iso ry co m m ittee’ s n o te (2 00 0 ). 69 NAS F ORE

NSI C S CI ENCE RE PORT , su pra n o te 3 , at 4

. 70 Id

. at 2 1

. 

### 12

### The Supreme Court identified the same concern in D aubert : “Expert

evidence can be both powerful and quite misleading because of the difficulty in evaluating it.” 7 1 

### Moreover, Federal Rule of Evidence 403 provides: “The court may exclude 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 2 

### I n this context, “misleading” does not imply an intent to mislead; the effect of the testimony on the jury

is the focus of Rule 403. I n short, a jury can be misled even in the absence of an intent to mislead. Courts are concerned about the “CSI effect” — i.e., “scientific proof may in some instances assume a posture of my stic infallibility in the ey e s of a jury

of lay men.” 7 3 

### Courts often exclude poly

graph evidence on this basis. 7 4 

### Certain terms should not used in presenting expert testimony because they are either invalid or confusing. Other terms should not used at trial without an explanation because of their potential to mislead the trier of fact. A. “Zero Error Rate”
I n United States v. Havvard , 7 5 

### which involved a Daubert challenge to fingerprint evidence, the expert claimed that the “error rate for the method is z e ro.” 7 6 

### Note the word method in the above quote. Examiners argued that, while individual examiners may make mistakes, the methodology itself is perfect. However, the dichotomy

between “methodological” and “human” error rates in this context is “practically meaningless” 7 7 

### because the examiner is the method. 7 8

71 Dau

b ert v . Merrell Do w

P h arm ., In c., 5 09 U.S. 5 7 9 , 5 9 5 (1 9 9 3 ) (q u o tin gJ ack B. W ein stein , Ru le 7 02 o

f th e Fed era l Ru les o

f Eviden ce Is S

o u n d : It S ho u l d No t Be Amen d

ed , 1 3 8 F.R.D. 6 3 1 , 6 3 2 (1 9 9 1 )).

72 F E D
. R. E V I D
. 4 0 3 (em p h asis ad d ed ). 73 Un itedStates v . Ad d iso n , 4 9 8 F.2 d7 4 1 , 7 4 4 (D.C. Cir. 1 9 7 4 ). 74 S

ee Un itedStates v . Call, 1 2 9 F.3 d1 4 0 2 , 1 4 0 6 (1 0 th Cir. 1 9 97 ) (“ Th ere is also th e d an g er th at th e j ury

m ay o v erv alu e p o ly g rap h

resu lts as an

in d icato r o f

tru th f u ln ess b ecau se o f th e p o ly g rap h ’ s scien tif

ic n atu re.”); Un itedStates v . Falsia, 7 24 F.2 d1 3 3 9 , 1 3 4 2 (9 th Cir. 1 9 8 3 ) (n o tin g p o ly g rap h ’ s “ m islead i n g ap p earan ce o f accu racy ”). 75 1 1 7 F. Su

p p. 2 d 8 4 8 (S.D. In d . 2 0 0 0 ), a ff’d , 2 60 F.3 d5 9 7 (7 th

Cir. 2 0 01 ). 76 Id

. at 8 5 4. 77 J enn if

er L . Mn o o k in , Fin gerp rin t Eviden ce in a n Ag e o f DNA Pro

filin g , 6 7 B ROOK
. L

. RE V . 1 3, 6 0 (2 0 0 1 ). P ro f esso r Mn o ok in

g o es o n to p ro v id e th is an alo g y : “ Th e sam e arg um en t co u ldb e m ad e o f ey ew itn ess testim o ny , a n o t orio u sly unreliab le f

o rm o f ev id en ce. P eo p le are all d istin ct f

ro m o n e an o th er in o b s erv ab le w ay s; th eref ore th e th eo retical erro r rate o f ey ew itn ess id entif

icatio n is zero , th o u g h

inp ractice o bserv ers m ay f req u ent ly m ak es erro rs.” Id

. S ee a lso Sim o n

A. Co l e, Mo re Th a n Zero : Acco u n tin g fo r Erro r in La ten t Fin g erp r in t Iden tifica tio n , 9 5 J

. C RIM
. L

. & C RIMI NOL OG Y 9 8 5 , 1 04 0 (2 0 0 5 ) (“ in f in g erp rin t p ractice th e co n cep t is v acu o u s”). P ro f esso r Co le id en tif

iedtw enty

- tw o m i sid en tif icatio n s, w

h ichh e arg u es “ are m o st lik ely

o n ly th e tip o f th e p ro v erb i al iceb erg o f actu al cases o f

f in g erp rin t m isattrib utio n .” Id

. at 9 9 1. Th e m isid entif icatio n cases in clu d e so m e th at in v o lv ed(1 ) v erif icatio n b y o n e o r m o re 

### 13

### The 2009 NAS report addressed this point: “Although there is limited

information about the accuracy and reliability

of friction ridge analy ses, claims that these analy ses have z ero error rates are not scientifically plausible.” 7 9 

### The report goes on to observed: “Some in the latent print community argue that the method itself, if followed correctly . . . has a z ero error rate. Clearly , this assertion is unrealistic . . .. The method, and the performance of those who use it, are inextricably

linked, and both involve multiple sources of error (e.g., errors in executing the process steps, as well as errors in human judgment.)” 8 0 

### Several courts also commented on this issue. For example, in United States v. Mitchell , 8 1 

### the Third Circuit wrote: “Testimony at the Daubert

hearing indicated that some latent fingerprint examiners insist that there is no error rate associated with their activities . . . . This would be out-of-place under Rule 702.” 8 2 

### The same issue arose in a firearms identification case. I n United States v. Glynn , 8 3 

### the court wrote that “[ t] he problem is compounded by the tendency of ballistics experts . . . to make assertions that their matches are certain bey ond all doubt, that the error rate of their methodology is ‘z ero,’ and other such pretensions.” 8 4


### B. “Hundred Percent Accurate”
I n a different firearms identification case, U nited States v. Monteiro , 8 5 

### the court noted: [ T] he examiners testified to the effect that they could be 100 percent sure of a match. Because an examiner’s bottom line opinion as to an identification is largely a subjective one , there is no reliable statistical or scientific methodology

which will currently

permit the expert to testify that it is a “match” to an absolute certainty , or to an arbitrary degree of

o th er ex am in ers, (2 ) ex am in ers certif iedb y th e In tern atio n al Asso ciatio n o f Id entif icatio n , (3 ) p ro ced ures u sin g a six teen

- p o in t stan d ard , an d(4 ) d ef

en se ex p erts w

h o co rro bo rated m isid en tif

icatio n s m ad e b y

p ro secutio n

exp erts. 78 S

ee San d y L . Z ab ell, Fin g erp rin t Eviden ce , 1 3 J .L

. & P O L ’ Y 1 4 3, 1 7 2 (2 00 5 ) (“ But, g iv en

its un av o id ab le su

b j ectiv e co m

p o n ent, inlaten t p rint ex am in atio n p eo p le a re th e p ro cess.”) (em

p h asis ad d ed ). 79 NAS F ORE

NSI C S CI ENCE RE PORT , su pra n o te 3 , at 1 4 2

. 80 Id

. at 1 4 3. 81 3 6 5 F.3 d2 1 5 (3 dCir. 2 0 0 4 ) (ad m ittin gf i n g erp rin t ev id en ce). 82 Id

. at 2 4 5- 4 6 . Ru le 7 0 2 is th e g ov ern in g ru le o n expert testim ony . 83 5 7 8 F. Su

p p. 2 d 5 6 7 (S.D.N.Y. 2 0 0 8 ). 84 Id

. at 5 7 4. 85 4 0 7 F. Su

p p. 2 d 3 5 1 (D. Mass. 2 00 6 ).



### 14

### statistical certainty

. 8 6



### The 2009 NAS report concurred: “The insistence by some forensic practitioners that their disciplines employ methodologies that have perfect accuracy and produce no errors has hampered efforts to evaluate the usefulness of the forensic science disciplines.” 8 7


### I n its first report on DNA profiling, the National Academy of Sciences report commented: “Prosecutors and defense counsel should not oversell DNA evidence. Presentations that suggest to a judge or jury that DNA ty

p ing is infallible are rarely

justified and should be avoided.” 8 8



### C. “Scientif

ic” The use of terms such as “science” or “scientific” in presenting expert testimony is also problematic. 8 9 

### I n 1995, a federal district court in United States v. Starzecpyzel

9 0 

### concluded that “forensic document examination, despite the existence of a certification program, professional journals and other trappings of science, cannot, after Daubert , be regarded as ‘scientific . . . knowledge.’”9 1 

### The court further stated that “while scientific principles may relate to aspects of handwriting analy sis, they have little or nothing to do with the day -to-day tasks performed by

[ Forensic Document Examiners] . . . . [ T] his attenuated relationship does not transform the FDE into a scientist.” 9 2 

### Although the court went on to admit the testimony as technical evidence, it placed conditions on its admissibility

. 9 3 

### Because FDEs use terms such as “laboratory

” and refer to authorities with titles containing the words “science” or “scientific,” there is a risk, according to the court, that jurors may bestow upon

86 Id

. at 3 7 2 (em

p h asis ad d ed ). 87 NAS F ORE

NSI C S CI ENCE RE PORT , su pra n o te 3 , at 4 7

. 88 N A T I ONA L RE SE A RCH C OUNCIL , N A T I O N A L A CA DE M Y OF S CI EN CE S , D NA T E CHNOL OG Y I

N F O RE NSI C S C I ENCE 2 6 (1 9 9 2). 89 P h ilo so p h ers o f

scien ce d isag ree ab o ut th e d ef in itio n o f “ scien ce.” Th e Su

p rem e Co urt q u o tedo n e d ef

in itio n in D a u b ert : KARL P OPPE R , C ONJE CT URE S A ND R E F UT A T I ONS : T HE G ROW T H OF S CI ENT I F I C K NOW LE DG E 37 (5 t

h ed . 1 98 9 ) (“ [T]h e criterio n o f th e scien tif

ic statu s o f

a th eo ry is its f alsif iab i lity , o r ref

utab ility , o r testab ility .”). D a u b ert , 5 09 U.S. at 5 9 3

. 90 8 8 0 F. Su

p p. 1 02 7 (S.D.N.Y. 1 99 5 ). 91 Id

. at 1 0 38

. 92 Id

. at 1 0 41

. 93 Inth e co urt’ s v iew , Da u b ert d i d n o t ap p ly

to n o n scien tif

ic ex p erts. Th e co urt relied o n th e f o llo w i n g statem en t in Da u b ert : “ Our d i scu ssio n is lim itedto th e scien tif

ic co n tex t b ecau se th at is th e n ature o f th e ex p ertise o f

f ered h ere.” 5 0 9 U.S. at 5 9 0 n .8 . Th is p o sitio n w as un d ercu t b y Ku mh o Tire , w h ichh eldth at all ex p ert testim o ny m u st p ass th e Da u b ert reliab ility test. Ku m

h o Tire Co ., L td . v . Carm ich ael, 5 2 6 U.S. 1 3 7, 1 49 (1 99 9). 

### 15

### FDEs the aura of the infallibility of science. The court approved a jury instruction, which stated that “FDEs offer practical, rather than scientific expertise.” 9 4 

### Similarly , in United States v. Glynn , 9 5 

### a firearms identification case, the court observed: “Based on the Daubert hearings . . . , the Court very quickly concluded that whatever else ballistics identification analy sis could be called, it could not fairly

be called ‘science.’” 9 6 

### The NAS report provides support for this position: “The law’s greatest dilemma in its heavy reliance on forensic evidence . . . concerns the question of whether — and to what extent — there is science in any given forensic science discipline.” 9 7 

### A subsequent passage concluded: “Among existing forensic methods, only

nuclear DNA analysis has been rigorously shown to have the capacity to consistently , and with a high degree of certainty , demonstrate a connection between an evidentiary sample and a specific individual or source.” 9 8 

### Other passages are in accord. 9 9 

### Many forensic identification disciplines are ultimately subjective, and there are often no meaningful standards 1 0 0 

### — factors that undercut claims that these techniques are “scientific.” 1 0 1

94 8 8 0 F. Su

p p. at 1 0 4 9

. 95 5 7 8 F. Su

p p. 2 d 5 6 7 (S.D.N.Y. 2 0 0 8 ). 96 Id

. at 5 7 0. 97 NAS F ORE

NSI CS S CI ENCE S RE PORT , s u pra n o te 3 , at 9

. 98 Id

. at 1 0 0. 99 “ Th e sim

p le reality

is th at th e in t erp retatio n

o f f o ren sic ev id en ce is n o t alw ay s b asedo n scien tif ic stu d ies to d eterm in e its v alid ity . Th is is a serio u s p ro b lem . Alth o u g h research h as b eend o n e in

so m e d i scip l in es, th ere is a n o tab le d earth o f p eer- rev iew ed , p u

b l i sh edstu d ies estab lish in g th e scien tif

ic b ases an dv alid ity

o f m any f o ren sic m eth o d s.” Id

. at 8 . “ Mu chf

o ren sic ev id en ce — in clu d in g , f

o r ex am p le, b ite m ark s an df

irearm an dto o lm ark

id en tif i catio n s — is in tro du ced incrim in al trials w ith out an y m ean in g f u l scien tif ic v alid atio n , d eterm in atio n o f erro r rates, o r reliab ility

testin g to ex p lain

th e lim i ts o f

th e d iscip l i n e.” Id

. at 1 0 7

- 0 8 100 “ Of

ten th ere are n o stan d ard p ro to co ls g o v ern in g f o ren sic p ractice ina g iv en d iscip lin e. An d , ev en

w h en p ro t o co ls are in p lace . . . , th ey o f ten are v ag u e an dn o t en f

o rced in any m ean in g f u l w ay .” Id

. at 6

. 101 J enn if

er L . Mn o o k in , et al., Th e Need fo r a Resea rch Cu l tu re in th e Fo ren sic S cien ces , 5 8 UCL A L . Rev . 7 2 5 , 7 3 1 (2 0 1 1 ) (“ Ino u r co llectiv e o p in io n , th e p atternid en tif icatio n d iscip lin es, as w ell as o th er f o rm s o f f o ren sic scien ce ev id en ce, m u s t b e p laced o n

a m o re rig o ro u s scien tif ic f o un d atio n . Mo re g en erally , w e b eliev e th at a sig n if i can t cu ltu

re sh if t is req u ired : Fo ren sic scien ce n eed s to f o cu s m o re o n

scien ce th an

o n law , to sh i f

t f ro m a q u asi- ad v ersarial p ersp ectiv e to a research o rien tatio n . In sh o rt, w e call f o r th e d ev elo p m en t an din stantiatio n o f w h at w e w ill term

a research cu ltu

re w ith in f o ren s ic scien ce”); J enn if

er L . Mn oo k in , Th e Co urts, Th e NAS , a nd th e Fu tu re o

f Fo ren sic S

cien ce , 7 5 B ROOK

L YN L

. RE V
. 1 2 0 9 , 1 2 1 5 (2 0 1 0 ) (“ Th is f o ren sic scien ce cu ltu

re — a cu l ture in w

h ichclaim s d eriv edf

ro m ex perien ce are o f

ten accep tedas a su b stitu t e f o r d ata; a cu l ture in w

h ichin terp retatio n s are o f ten f ram edinab so lute term s rath er th an inm o re lim itedo r m o d est lan g u ag e; a cu ltu re in w h i chp o ten tially

b iasin g in f

o rm atio n is n o t sy s tem atically

k ep t f ro m th e f o ren s ic ex am in er; an da cu ltu re in w h ichin stitu

tio n ally co zy relatio n sh ip s b etw eend etectiv es, f o ren sic an aly s ts, an d p ro secuto rs m ay en co urag e un co n scio u s 

### 16

### I n Kumho Tire , the Supreme Court rejected the distinction between

“scientific” and “technical” evidence for purposes of apply ing the Daubert

test, observing that the distinction would be difficult to draw. 1 0 2 

### Thus, the classification of evidence as scientific or nonscientific is not important for admissibility purposes; all expert testimony must satisfy

the Daubert validity /reliability

requirement. However, the term “scientific” may unduly impress the jury

. 1 0 3 

### There is little question that phy sical evidence (e.g., distinctive shoe print) can be probative and powerful even though it is not scientific.

D. “Reasonable Degree of Scientif ic Certainty” The expression “reasonable scientific certainty ,” which is often included (and sometimes demanded) in expert testimony , is another phrase that should be abandoned. 1 0 4


### 1. Lack of a Scientific Bases The phrase, which combines two suspect words — “scientific” 1 0 5 

### and

p artisan sh ip — rem ain s v ery m u chth e n o rm

w i th in f o ren sic scien ce lab o rato ries to d ay . It is, in th e en d , th is cu ltu

re th at n eed s to ch an g e; n ew an dim pro v edf o ren sic tech n iq u es w i ll n o t, b y th em selv es, p ro v id e anad eq u ate so lutio n .”).

102 Th e Co urt w

ro te: [I]t w o u ldp ro v e d i f

f icu lt, if n o t im p o ssib le, f

o r j u dg es to ad m in ister ev id en tiary ru les un d er wh icha g atek eep in g o b lig atio n d ep en d edu

p o n a d istin ctio n

b etw een“ scien tif

ic” k n o w led g e an d“ tech n i cal” o r “ o th er sp ecialized ” k n o w led g e. Th ere is n o clear lin e th at d iv id es th e o n e f

ro m th e o th ers. Discip lin es su chas en g in eerin g rest u p o n scientif ic k n o w led g e. P ure scien tif

ic th eo ry itself m ay d ep en df o r its d ev elo p m en t u

p o n o b serv atio n

an dp ro p erly

en g in eered m ach in ery . An dco n cep tu al ef f o rts to d istin g u ish

th e tw o are u n lik ely

to p ro du ce clear leg al lin es cap ab le o f ap p licatio n

inp articu lar cases. Cf

. Brief f o r Natio n al Acad em

y o f En g in eerin g as Amicu s Cu ria e 9 (scien tist seek s to un d erstan dn ature wh ile th e en g in eer seek s n ature’ s m o d if i catio n ); Brief

f o r Ru bb er Manu f acturers Asso ciatio n

as Amicu s Cu ria e 1 4- 1 6 (en g in eerin g , as an “ ‘ ap p lied scien ce,’ ” relies o n

“ scien tif ic reaso n i n g an dm eth o d olo g y ”); Brief f o r J o h n Allenet al. as Amici Cu ria e 6 (en g in eerin g relies up o n “ scien tif ic k n o w l ed g e an dm eth o d s ”). Ku mh o Tire , 5 2 6 U.S. at 1 4 8

.

103 S

ee Un itedStates v . Ad d i so n , 4 98 F.2 d7 4 1, 7 44 (D.C. Cir. 1 9 7 4 ) (“ [S]cien tif ic p ro o f m ay inso m e in stan ces assu

m e a p o stu

re o f m y stic in f allib ility inth e ey es o f

a j ury o f lay m en .”).

104 Th e term

“ reaso n ab le m ed ical certain ty ” is sim ilarly p ro b lem atic. 105 S

ee Un itedStates v . Gly

nn , 5 7 8 F. Su

p p . 2 d5 6 7 , 5 7 0 (S.D.N.Y. 2 0 0 8 ) (“ Based o n th e Da u b ert h earin g s . . . , th e Co urt v ery q u ick ly co n clu d edth at w

h atev er else b allistics id en tif icatio n an aly sis co u ldb e called , it co u ldn o t f airly b e called ‘ s cien ce.’ ”); Un itedStates v

. Starzecp y zel, 8 8 0 F. Su

p p . 1 0 2 7 . 1 0 3 8 , 1 0 41 (S.D.N.Y. 1 9 95 ) (“ f o ren sic d o cum en t ex am in atio n , d esp ite th e ex isten ce o f

a certif icatio n p ro g ram , p ro f

essio n al j o urn als an do th er trap pin g s o f 

### 17

### “certainty ” — has no scientific meaning. One scholar summed it up this way : The reasonable-degree-of-scientific-certainty language almost certainly was drafted by the lawy ers. Scientists have no use for this phrase (outside the courtroom). I

ndeed, “a reasonable degree of scientific certainty ” is not a defined concept in scientific disciplines or even in law. . . . I t is legal mumbo jumbo derived from archaic cases in which lawy ers discovered that if a medical doctor did not utter the incantation “to a reasonable degree of medical certainty ,” his testimony might be excluded because doctors were not supposed to talk about mere probabilities. Modern cases usually recogniz e that suitably

explained information about less-thancertain possibilities can be helpful in various circumstances, but experts want to (or are induced to) incant not only “medical certainty

” but also “clinical certainty ,” “psychological certainty ,” “psychiatric certainty ,” “engineering certainty ,” “architectural certainty ,” “ballistic certainty ,” “professional certainty ,” and even “forensic certainty ” and “legal certainty .” 1 0 6 

### The requirement that experts testify in terms of probability most likely originated as a “sufficiency

” rule in civil cases in which causation was an issue. The plaintiff in a civil action would have to prove causation by preponderance of evidence (i.e., more probable than not). The term may then have been improperly transmuted into an “admissibility ” rule in civil cases and then improperly applied in criminal cases. 1 0 7


### 2. Federal Rules of Evidence Article VI Iof the Federal Rules of Evidence, which governs expert testimony , does not require the use of the phrase “reasonable scientific (or medical) certainty , as some courts have recogniz ed: “There is no such requirement.” 1 0 8 

### I t is a common law requirement that, at least in theory , was

scien ce, can n o t, af

ter Da u b ert , b e reg ard ed

as ‘ scien tif

ic . . . k n o w l ed g e.’ ”; “ w

h ile scien tif

ic p rin cip les m ay

relate to asp ects o f

h an d w ritin g an aly sis, th ey

h av e little o r n o th in g to d o w ith th e d ay - to

- d ay

task s p erf

o rm edb y [Fo ren sic Do cum en t Ex am in ers] . . . . [T]h is atten u ated relatio n sh ip d o es n o t tran sf o rm th e FDE in to a scien tist.”). S ee a l so NAS F ORE

NSI CS S CI E

NCE S RE P ORT , su

p ra n o te 3 , at 9 , 1 0 7

- 0 8 (“ Th e law ' s g reatest d ilem m a inits h eav y

relian ce o n

f o ren sic ev id en ce . . . co n cern s th e q u estio n o f w h eth er — an dto w

h at ex ten t — th ere is scien ce inany g iv en f o ren sic scien ce d iscip lin e.”; “ Mu chf o ren sic ev id en ce — in clu d in g , f o r ex am p le, b ite m ark s an df irearm an dto o lm ark

id en tif icatio n s — is in t

ro du ced incrim in al trials w ith out an y m ean in g f u l scien tif ic v alid atio n , d eterm in atio n o f erro r rates, o r reliab ility

testin g to explain

th e lim its o f

th e d iscip lin e.”).

106 D AV I D H. K AY E , T HE D OUBL

E H E L I X A ND T HE L A W

OF E V I DEN CE 82 (2 01 0). 107 S

ee P AUL C. G I

A NNE LL I , B A L

DW I N ’ S O H I O P RA CT I C E , E V I DENCE § 7 0 2 .6 (3 ded

. 2 0 1 0 ) (d escrib in g th e Oh io ex p erien ce w ith th e term ). 108 Un itedStates v . Cy p h ers, 5 5 3 F.2 d1 0 6 4 , 1 0 7 2 (7 th Cir. 1 9 7 7). 

### 18

### abolished by Federal Rule 402, which makes all relevant evidence in the absence of a rule of exclusion. 1 0 9


### 3. Ambiguous and Misleading Although the phrase is used frequently in cases, its legal meaning is ambiguous at best. 1 1 0 

### One commentator observed: “Although judges expect, and sometimes insist, that expert opinions be expressed with ‘reasonable medical certainty ,’ and although attorney s ritualistically intone the phrase, no one knows what it means! No consensus exists among judges, attorneys, or academic commentators as to whether ‘reasonable medical certainty ’ means ‘more probable than not’ or ‘bey

ond a reasonable doubt’ or something in between.” 1 1 1 

### The ambiguity

of the term is illustrated in Burke v. Town of W a lpole , 1 1 2 

### a bite mark identification case. The First Circuit had to interpret the term as used in an arrest warrant: [ W ] e must assume that the magistrate who issued the arrest warrant assigned no more than the commonly accepted meaning among lawy ers and judges to the term “reasonable degree of scientific certainty ” — “a standard requiring a showing that the injury was more likely than not caused by a particular stimulus, based on the general consensus of recogniz ed [ scientific] thought.” Black’s L aw Dictionary 1294 (8th ed.2004) (defining “reasonable medical probability ,” or “reasonable medical certainty ,” as used in tort actions). That standard, of course, is fully consistent with the probable cause standard. 1 1 3 

### Note that the case involved a magistrate, not a jury

. I t seems doubtful that a jury

109 Ed w ardJ . Imw ink elried & Ro b ert G. Sco f ield , Th e Reco gnitio n o

f a n Accu sed 's Co n stitu tio n a l Rig h t to In tro d u ce Exp ert Testimo ny Atta ckin g th e W eigh t o f Pro secu tio n S

cien ce Eviden ce: Th e An t id

o te fo r th e S

u p reme Co urt's Mista ken Assu mp tio n in Ca lifo r n ia v. Tro mb etta , 3 3 Ariz. L . Rev . 5 9 , 6 9 (1 9 9 1 ) (“ Many co urts co ntin

u e to ex clu d e o pin io n s w

h ichf all sh o rt o f exp ressin g a p ro b ab ility

o r certain ty . . . . Th ese o p in i on s h av e b eenex clu d edinj urisd ictio n s w h ichh av e ad o ptedth e Fed eral Ru les o f Ev i d en ce.”). 110 So m etim es th e p h rase seem s to b e u sedas a co n f id en ce statem en t (i.e., “ I am co n f id en t o f m y o p in io n .”), in w

h i chcase th e ex p ert co u ldav o idth e p h rase alto g eth er an d d irectly testif y h o w co n f id en t sh e is inh er o p in io n . S

ee J am es E. Hu llv erso n , Rea s o na b le Deg ree o f Med ica l Certa in ty: A To rt et a Tra vers , 3 1 S T
. L OUI S U.L .J

. 5 7 7 , 5 8 2 (1 9 8 7 ) (“ [T]h ere is n ev erth eless an

un d ercu rren t th at th e ex p ert inf ed eral co urt ex p ress so m e b asis f or b o th th e co n f id en ce w ith

w h ichh is co n clu sio n

is f o rm ed , an dth e p ro b ab ility th at h is co n clu sio n

is accu rate.”).

111 J ef

f L . L ew in , Th e Gen esis a n d Evo lu tio n o

f Leg a l Un certa in ty Ab o u t “Rea so n a b le Med ica l Certa i n ty, ” 5 7 M D
. L

. RE V
. 3 8 0 (1 9 9 8 ).

112 4 0 5 F.3 d6 6 (1 st Cir. 2 0 0 5 ). 113 Id

. at 9 1 (em

p h asis ad d ed ). 

### 19

### would understand that the term “reasonable scientific certainty ” meant only

“more probable than not” — i.e. , 51 percent. I t is more likely

that the jury

would understand the term to mean 95% certain or perhaps “bey ond a reasonable doubt.” The problem could be rectified by using the phrase “more probable than not” rather than “reasonable scientific certainty .” However, this solution introduces it own problems. Federal Rule 401 requires only that evidence be relevant, not probable. For example, evidence that a suspect had a .38 caliber handgun and that a .38 caliber bullet was found during a murder victim’s autopsy satisfies Rule 401. 1 1 4 

### But the expert could not say that suspect’s handgun probablyfired the bullet. 1 1 5


### 4. Recent Cases The phrase has come under attack in recent cases. I n United States v. Glynn , 1 1 6 

### the court ruled that the term “reasonable scientific certainty ” could not be used in a firearms identification case. I n light of the expert’s admission concerning the subjective nature of the examination, “the Government did not seriously contest the Court’s conclusions that ballistics lacked the rigor of science and that, whatever else it might be, its methodology was too subjective to permit opinions to be stated to ‘a reasonable degree of ballistic certainty.’” 1 1 7 

### Similarly , in United States v. Taylor , 1 1 8 

### the court wrote: “[ B] ecause of the limitations on the reliability of firearms identification evidence discussed above, [ the expert] will not be permitted to testify that his methodology

allows him to reach this conclusion as a matter of scientific certainty. [ T he expert] also will not be allowed to testify

that he can conclude that there is a match to the exclusion, either practical or absolute, of all other guns. He may only testify that, in his opinion, the bullet came from the suspect rifle to within a reasonable degree of

114 Fed . R. Ev id . 4 0 1 (“ Ev id en ce is relev an t if : (a) it h as an y

ten d en cy to m ak e a f

act m o re o r less p ro b ab le th an it w o u ldb e w ith o ut th e ev id en ce; an d(b ) th e f act is o f co n sequ en ce in d eterm in in g th e actio n .”).

115 Th is ty

p e o f ev id en ce h as b eenad m i ttedinnum ero u s cases. S ee, e.g ., P eo p le v

. Ho rn in g , 1 0 2 P .3 d2 2 8 , 2 3 6 (Cal. 2 0 0 4 ) (ex p ert “ o p in edth at b o th b u l lets an dth e casin g co u l d h av e b eenf

ired f ro m th e sam e g un

. . . b ecau se o f

th eir co n d itio n

h e co u ldn o t

say f or sure”); L uttrell v . Co m

m o nw ealth , 9 5 2 S.W .2 d2 1 6 , 2 1 8 (Ky . 1 9 9 7 ) (ex p ert “ testif iedo n ly th at th e b u l lets w h ichk illedth e v i ctim

co u ldh av e b eenf

ired f ro m L u ttrell’ s g un ”). 116 5 7 8 F. Su

p p. 2 d 5 6 7 (S.D.N.Y. 2 0 0 8 ). 117 Id

. at 5 7 1. In Un ited S ta tes v. W

illo ck , 6 96 F. Su

p p . 2 d5 3 6 , 5 4 9 (D. Md . 2 0 1 0 ), b asedo n a co m p reh en siv e m ag istrate’ s rep o rt, th e co urt h eldth at “ [th e ex p ert] sh all n o t o p in e th at it is a ‘ p ractical im

p ossib ility ’ f

o r a f irearm to h av e f ired th e cartrid g es o th er th an th e co m m o n ‘ un k n o w n f irearm ’ to w

h ich[th e ex p ert] attrib utes th e cartrid g es.” Th u s, “ [Th e ex p ert] sh all state h is o p in i o n s an d co n clu sio n s w ith o ut an y ch aracterizatio n

as to th e d eg ree o f

certain ty w ith w h ich h e h o ld s th em .” Id

.

118 6 6 3 F. Su

p p. 2 d 1 1 7 0 (D. N.M. 2 0 0 9 )



### 20

### certainty in the firearms examination field.” 1 1 9 

### However, replacing the term “reasonable scientific certainty ” with the term “reasonable ballistic certainty ” does not solve the problem. 1 2 0 

### That phrase suffers from the same defects. I

n sum, the phrase should be abandoned. J urisdictions that require the phrase “reasonable scientific (or medical) certainty ” should reconsider its use. E. Claim s of “uniqueness” Courts have responded in different way s to claims of uniqueness. Due to a lack of foundational research, 1 2 1 

### several courts have limited the scope of handwriting testimony , permitting expert testimony about the similarities and dissimilarities between exemplars but not the specific conclusion that the defendant was the author (“common authorship” opinion). 1 2 2 

### Although the courts have used this approach most frequently in questioned document cases, they have sometimes applied it to other ty pes of forensic expertise such as firearms identification examinations. 1 2 3 

### One court took a less restrictive approach, ruling

119 Id

. at 1 1 80

. 120 S

ee a lso Un itedStates v . Diaz, No . CR 0 5

- 00 1 6 7 W H A, 2 0 0 7 W L 4 8 5 96 7 , at * 1 (N.D. Cal. Feb . 1 2, 2 0 0 7 ) (“ [T]h e ex am in ers w h o testif y inth is case m ay

o n ly testif y th at a m atch h as b eenm ad e to a ‘ reaso n ab l e d eg ree o f certain ty in th e b allistics f

ield .’ ”); Un itedStates v

. Mo n teiro , 4 0 7 F. Su

p p . 2 d3 5 1 , 3 7 2 (D. Mass. 2 0 0 6); Co m m onw ealthv . P y

to u Hean g , 9 4 2 N.E.2 d 9 2 7 , 9 4 5 (Mass. 2 0 1 1 ) (“ W h ere a q u alif iedex p ert h as id en tif

iedsu f f icien t in d iv idu al ch aracteristic to o l m ark s reaso n ab ly

to o f f er an o p in io n

th at a p articu lar f

irearm f ired a p ro j ectile o r cartrid g e casin g reco v ered as ev id en ce, th e ex p ert m ay o f f er th at o p in io n

to a ‘ reaso n ab le d eg ree o f b allistic certain ty .’ ”).

121 S

ee Un itedStates v . Hid alg o , 2 29 F. Su pp . 2 d9 61 , 9 6 7 (D. Ariz. 2 0 0 2 ) (“ Becau s e th e p rin cip le o f un iq u en ess is w ith o ut em p i rical su p p o rt, w e co n clu de th at a d o cum en t ex am in er w ill n o t b e p erm ittedto testif y th at th e m ak er o f

a kn ow n d o cum en t is th e m ak er o f th e q u estio n edd o cu

m en t. No r w ill a d o cum en t ex am i n er b e ab le to testif y as to id en tity

interm s o f p ro b ab ilities.”); Un itedStates v . Fu j ii, 1 5 2 F. Su

p p . 2 d9 3 9 , 9 4 0 (N.D. Ill. 2 0 0 0 ) (“ Han d w ritin g an aly sis d o es n o t stan du

p w ell un d er th e D a u b ert s tan d ard s. Desp i te its lo n g h isto ry o f u se an d accep t an ce, v alid atio n

stu d ies su

p po rtin g its reliab ility

are f ew , an dth e f

ew th at ex ist h av e b een criticized f

o r m eth o d o l o g ical f

law s.”). 122 S

ee Un itedStates v . Osk o w itz, 2 9 4 F. Su pp . 2 d3 7 9 , 3 8 4 (E.D.N.Y. 2 0 0 3) (“ Man y o th er d istrict co urts h av e sim ilarly p erm i tteda h an d w

ritin g ex p ert to an aly ze a writin g sam p le f o r th e j u ry w ith o ut p erm ittin g th e ex p ert to o f f er an o p i n io n

o n th e u ltim ate q u estio n

o f au th o rsh ip .”); Un itedStates v . Ru th erf o rd , 1 0 4 F. Su

p p . 2 d1 19 0 , 1 1 9 4 (D. Neb . 2 0 0 0 ) (“ [T]h e Co urt co n clu d es th at FDE Rau sch er’ s testim o ny m eets th e req u i rem en t s o f Ru l e 7 02 to th e ex ten t th at h e lim its h is testim o ny to id entif y in g an dexp lain in g th e sim ilarities an d d issimilarities b etw eenth e k

n o w n ex em plars an dth e q u estio n ed

d o cum en ts. FDE Rau sch er is p reclu dedf ro m ren d erin g an y

u l tim ate co n clu s io n s o n

au th o rsh ip o f

th e q u estio n edd o cum en t s an d is sim ilarly p reclu d edf

ro m testif y in g to th e d eg ree o f

co n f id en ce o r certain t

y o n w h i chh i s o p in io n s are b ased .”); Un itedStates v . Hin es, 5 5 F. Su p p . 2 d6 2 , 6 7 (D. Mass. 1 9 9 9 ) (h o ld in g th at ex p ert testim o ny co n cern i n g th e g en eral sim ilarities an dd if f eren ces b etw eena d ef

en d an t’ s h an d w

ritin g ex em p lar an da stick

u p n o te w as ad m issib le b ut n o t th e sp ecif ic co n clu sio n

th at th e d ef

en d an t w as th e au th o r).

123 S

ee Un itedStates v . Green , 4 0 5 F. Su pp . 2 d1 0 4 , 1 0 7 (D. Mass. 2 0 0 5 ). 

### 21

### that the expert would be permitted to testify only that it was “more likely

than not” that recovered bullets and cartridge cases came from a particular weapon. 1 2 4 

### “To the Exclusion of All Others” Experts have frequently

testified that they have made a match “to the exclusion of all other firearms.” 1 2 5 

### This is simply another way

of claiming uniqueness. In United States v. Green , 1 2 6 

### the court questioned such testimony : “[ The expert] declared that this match could be made ‘to the exclusion of every other firearm in the world.’ . . . That conclusion, needless to say , is extraordinary , particularly

given [ the experts] data and methods.” 1 2 7 

### Further, in 2008, a y e ar before the NAS report on forensic science was issued, a different NAS report, one on computeriz ed ballistic imaging, addressed this issue. The report cautioned:

“ Conclusions drawn in firearms identification should not be made to imply the presence of a firm statistical basis when none has been demonstrated. ” 1 2 8 

### I n particular, that report was concerned about testimony cast “in bold absolutes” such as that a match can be made to the exclusion of all other firearms in the world: “Such comments cloak an inherently subjective assessment of a match with an extreme probability statement that has no firm grounding and unrealistically

implies an error rate of z ero.” 1 2 9 

### Several courts are in accord. 1 3 0 

### “Individualization”
I t is easier to identify

what an expert should not say than to prescribe what an expert may

legitimately

opine at trial. Some scholars have questioned whether individualiz ation is even achievable. 1 3 1 

### Other scholars do not accept this “radical

124 Un itedStates v . Gly nn , 5 7 8 F. Su

p p . 2 d5 6 7 , 5 7 5 (S.D. N.Y. 2 0 0 8 ). 125 S

ee FBI H A

N DBOOK

OF F ORE

NSI C S CI ENCE S 5 7 (rev . ed . 1 9 9 4 ). 126 Un itedStates v . Green , 4 0 5 F. Su p p . 2 d1 04 (D. Mass. 2 0 0 5 ). 127 Id

. at 1 0 7 (citatio n s o m itted ). 128 N A T I ONA L RE SE A RCH C OUNCIL , N A T I O N A L A CA DE M Y OF S CI EN CE S , B A L L I ST I C I MA G I NG 8 2 (2 0 08 ) (em

p h asis in o rig in al). 129 Id

. 130 S

ee Un itedStates v . Alls, slip o p in i on , No . CR2

- 0 8

- 2 2 3 (1 ) (S.D. Oh i o Dec. 7 , 2 0 0 9 ) (“ [T]h is Co urt f

o llo w s th e ap p ro achtak en b y Glyn n , Mo nteiro , Green , Dia z an d Mo u zo n e, an dp laces a lim itatio n

o n [th e ex pert] testim o ny . Alth o u g h [th e ex p ert] m ay

testif y as to h er m eth o d o lo g y , case w o rk , an do b serv atio n s in reg ard s to th e casin g co m pariso n sh e p erf o rm edf o r th is case, sh e m ay

n o t testif y as to h er o p in io n

o n w h eth er th e casin g s are attrib ut ab le to a sin g l e f irearm to th e ex clu sio n

o f all o t h er f irearm s. Su chtestim o ny

w o u ldb e m islead in g an dp rej u d icial g iv en th e in h eren t su

b j ectiv ity inFirearm

an dTo o lm ark

Id ent if icatio n .”); Un itedStates v . Diaz, No . CR 0 5

- 0 0 1 6 7 W HA, 2 0 0 7 W L 4 8 5 9 6 7 , at * 1 (N.D. Cal. Feb . 1 2, 2 00 7 ).

131 Mich ael J . Sak s & J o n ath an J . Ko eh ler, Th e In d ivid

u a liza t io n Fa lla cy in Fo ren sic S

cien ce Evid en ce , 6 1 V A ND
. L

. RE V
. 1 9 9 , 2 0 5 (2 0 0 8 ) (“ Th e co n cep t o f
‘ in d iv idu alizatio n ,’ w

h ichlies at th e co re o f

num ero u s f

o ren sic scien ce su

b f i eld s, ex i s ts o n l y

ina m etap h y sical o r rh eto rical sen se. It h as n o scien tif i c v alid ity , an dit is su stain edlarg ely b y th e 

### 22

### skepticism” and believe that such an approach would mislead the jury in the other direction — by

vitiating the probative value of the evidence. 1 3 2 

### This position, however, does not endorse the overstatements described above. Nor does it minimiz e the risk of misleading the jury or give the expert carte blanche authority : L e t us assume that the jury gets the message — a match is not an absolute identification. Can the criminalist do something more to explain its probative value? Obviously , this depends on what is known about the frequency of the identify

ing trait in the relevant population. Are the features very common, rarely seen, or somewhere in between? There will be occasions when such qualitative testimony is reasonable. W hen no duplicates have been seen after sy stematic, careful and (one hopes) representative studies, a criminalist determined to refer to uniqueness might even assert that a trait is either unique or very rare in a population. 1 3 3


### F. “Consistent With” The phrase “consistent with” has long been recogniz ed as problematic. The controversial Sacco and Vanz etti case, in which the defendants were executed for a murder during a pay roll robbery

in 1921, is illustrative. Firearms identification evidence play ed a critical role in this prosecution. After reviewing the case, Professors Morgan and J oughin, wrote: On October 23 Captain Proctor made an [ post-trial] affidavit indicating that he had repeatedly

told [ the prosecutor] that he would have to answer in the negative if he were asked whether he had found positive evidence that the fatal bullet had been fired from Sacco’s pistol. The statement which Proctor made on the witness stand was: “My opinion is that it is consistent with being fired by that pistol.” 1 3 4


### W hat does the term “consistent with” mean in hair analy sis? The probative value of this conclusion would, of course, vary if only a hundred people had microscopically

indistinguishable hair as opposed to several million. The crime scene hair could have come from 5 other persons — or 10, 50, 100, 500, 1,000, 100,000, and so forth. As one hair examiner wrote: “If a pubic hair from the scene of a crime is found to be similar to those from a known source, [ the

f au lty lo g ic th at eq u ates in f

req u en cy w ith un iq u en ess.”). 132 Dav idH. Kay e, Pro b a b i lity, In d ivid u aliza tio n a n d

Un i q u en ess in Fo ren sic S cien ce Evid en ce: Listen in g to th e Aca d

emies , 7 5 B ROOK
. L

. RE V
. 1 1 6 3 , 1 1 8 5 (2 0 1 0). 133 Id

. at 1 1 80

. 134 L OUI S J OUG HI N & E DMUND M. M ORGA N , T HE L E G A C Y OF S A C CO & V A NZ E T T I 1 5 (1 9 4 8). Th ese au th ors co n clu d ed : “ Inef f ect it is anact o f

self

- im peach m en t b y

o n e o f th e exp erts w h o testif iedf o r th e p ro secutio n

at th e Ded h am

trial.” Id

. 

### 23

### courts] d o not know whether the chances that it could have originated from

another source are one in two or one in a billion.” 1 3 5


### G. “Match” Professor Berger put it this way : W e allow eye witnesses to testify that the person fleeing the scene wore a y ellow jacket and permit proof that a defendant owned a y ellow jacket without establishing the background rate of y e llow jackets in the community

. J urors understand, however, that others than the accused own y ellow jackets. W hen experts testify about samples matching in every respect, the jurors may

be oblivious to the probability concerns if no background rate is offered, or may be unduly

prejudiced or confused if the probability

of a match is confused with the probability of guilt, or if a background rate is offered that does not have an adequate scientific foundation. 1 3 6


### VII. D E C L A R

A T I O N O F 

### E X P E RT I S E 

### ABA Civil Trial Practice Standard 14 provides: “The court should not, in the presence of the jury , declare that a witness is qualified as an expert or to render an expert opinion, and counsel should not ask the court to do so.” 1 3 7 

### This policy was later extended to criminal cases. As one court remarked, Great care should be exercised by a trial judge when the determination has been made that the witness is an expert. I f the jury is so informed such a conclusion obviously

enhances the credibility

of that witness in the ey es of the jury . All such ruling should be made outside the hearing of the jury and there should be no declaration that the witness is an expert. 1 3 8


### I n 1994, J udge Richey

recommended this approach, noting that such a practice “ensures that trial courts do not inadvertently put their stamp of authority” on a

135 B.D. Gau d ette, Pro b a b ilities a nd Hu ma n Pu b ic Ha ir Co m

p a riso n s, 2 1 J

. F ORE NSI C S C I
. 5 1 4 , 5 1 4 (1 97 6 ). 136 Marg aret A. Berg er, Pro ced u ra l Pa ra d igms fo r Ap

p lyin g th e Dau b ert Test , 7 8 M I NN
. L

. RE V
. 1 3 4 5 , 1 3 57 (1 9 9 4 ).

137 ABA C IV I L T RI A L P RA CT I CE S T A

NDA RD 1 4 (2 0 0 7 ). 138 L uttrell v . Co m

m o nw ealth , 9 5 2 S.W .2 d2 16 , 2 1 8 (Ky . 1 9 9 7 ). S ee a lso Un i ted States v . L au

rien ti, 6 1 1 F.3 d 5 3 0 , 5 4 7 (9 th Cir. 2 0 1 0 ) (“ To th e ex ten t th at Def en d an t s arg u e th at th e d istrict co u

rt ab u sedits d i scretio n

b y f ailin gto d escrib e Mey er as an ‘ ex p ert’ in f ro n t o f th e j ury , w e d isag ree. Th e d eterm in atio n th at a w itn ess is an

ex p ert is n o t anex p ress im p rim atur o f sp ecial cred en ce; rath er, it is sim p ly a d ecisio n

th at th e w itn ess m ay

testif y to m atters co n cern i n g ‘ scien tif ic, tech n ical, o r o th er sp ecialized k n o w led g e.’ Fed .R.Ev id . 7 0 2 .”). 

### 24

### witness’ opinion, and protects against the jury ’s being “overwhelmed bythe socalled ‘experts.’” 1 3 9


### IX. A T T O R

N E Y 

### C O M P E T E N C E



### A. Ethical Duty Perhaps the most basic of all professional ethical precepts is competence. I ndeed, it appears as the first of the ABA Model Rules of Professional Conduct: “A lawyer shall provide competent representation to a client. Competent representation requires the legal knowledge, skill, thoroughness and preparation reasonably

necessary

for the representation.” 1 4 0 

### An accompany ing comment explains that relevant factors in determining whether a lawy e r acts competently include “the relative complexity and specializ ed nature of the matter.” 1 4 1 

### Thus, questions of competence under Model Rule 1.1 can be broken down into issues of expertise and preparation. The first — which the rule refers to with the words “knowledge” and “skill” — deals with the capability of a lawyer to handle a particular representation. The second — which the rule refers to with the words “thoroughness and preparation” — deals with the time and effort the lawy er invests in preparing the case. I n o ther words, a lawy

er may violate the duty of competence by

lacking sufficient knowledge of a particular area of law. Or, even if the lawy

er has sufficient expertise, the lawy er may violate the duty

of competence by

failing to investigate and prepare the case sufficiently

. No attorney

can try criminal cases today without a grounding in forensic evidence. The ABA has adopted the following recommendations: (1) “Training in forensic science for attorney s should be made available at minimal cost to ensure adequate representation for both the public and defendants,” and (2) “Counsel should have competence in the relevant area or consult with those who do where forensic evidence is essential in a case.” 1 4 2



### B. Right to Ef

f e ctive Assistance of

Counsel
I n addition, the Sixth Amendment right to counsel includes the right to

139 Ch arles Rich ey , Pro p o sa ls to Elimin ate th e Preju d i cia l Effect o f th e Use o

f th e W o rd “Exp ert” Un d

er th e Fed era l Ru les o

f Eviden ce in Civil a n d Crimin a l Ju ry Tria ls , 1 54 F.R.D. 5 3 7 , 5 5 9 (1 9 9 4 ).

140 ABA M ODE L R ULE S OF P ROF ’ L C ONDUCT R. 1 .1

. 141 Id

. at R. 1 .1 cm

t. 1

. 142 RE PORT OF T HE ABA C RIMI NA L J UST I CE S E CT I ON ’ S A D H OC I NNOCE NCE C OMMI T T E E T O E NSURE T HE I NT E G RI T Y OF T HE C RIMI NA L P R OCE SS , A C HI E V I NG J UST I CE : F RE E I

NG T HE I NNOCE

NT , C O NV I CT I

NG T HE G UI L T Y 4 7 (P au l C. Gian n elli & My rn a Raed er ed s . 2 00 6 ). 

### 25

### effective assistance of counsel. 1 4 3 

### The Supreme Court has decided several recent

cases on the subject. I

n H arrington v. Richter, 1 4 4 

### the Court wrote: “Criminal cases will arise where the only reasonable and available defense strategy requires consultation with experts or introduction of expert evidence.” 1 4 5 

### I n Hinton v. Alabama , 1 4 6 

### the Court found counsel ineffective for failing to understand how to apply for funds in order retain a defense expert. I n many of the cases cited earlier, defense counsel failed to provide adequate representation.
X. C L O S I N G 

### A R GU ME N T 

### Properly presented evidence may

become misleading due to its characteriz ation in closing argument to the jury

. 1 4 7 

### W illiamson (discussed above) exemplifies this issue. I n summation, the prosecutor claimed: “[ T ]here’s a match.” 1 4 8 

### Even the state court misinterpreted the evidence, writing that the “hair evidence placed [ petitioner] at the decedent’s apartment.” 1 4 9 

### As noted above, using the term “match” — without further explication — may be misleading. Similarly , in People v. Linscott 1 5 0 

### the I llinois Supreme Court found that the prosecutor improperly

argued that hairs collected from the victim’s apartment “were conclusively

identified as coming from defendant’s head and pubic region. There simply

was not testimony

at trial to support these statements. I n fact, [ the prosecution experts] and the defense hair expert . . . testified that no such identification was possible.” 1 5 1 

### L inscott was subsequently exonerated by

DNA evidence. 1 5 2


### I n United States v. Hebshie , 1 5 3 

### an arson case involving an accelerant143 S

ee Ev itts v . L u cey , 4 6 9 U.S. 3 8 7 , 3 9 6 (1 9 8 5 ) (“ [A] p arty w h o se co un s el is un ab le to p ro v id e ef

f ectiv e rep resen tatio n

is in n o b etter p o s itio n

th an o n e w h o h as n o co un sel at all.”). 144 1 3 1 S. Ct. 7 7 0 (2 0 1 1 ).

145 Id

. at 7 8 8. 146 1 3 4 S. Ct. 1 0 81 (2 0 1 4 ). 147 S

ee Dard en

v . W ainw

rig h t, 4 7 7 U.S. 1 68 , 1 8 1

- 8 2 (1 9 8 6 ) (“ Th e p ro secuto rs’ arg um en t d idn o t m an ip u late o r m isstate th e ev id en ce . . . .”).

148 9 0 4 F. Su

p p. at 1 5 5 7

. 149 W illiam so n

v . State, 8 1 2 P .2 d3 8 4 , 3 9 7 (Ok la. Crim . Ap p. 1 99 1 ). 150 5 6 6 N.E.2 d1 3 5 5 (Ill. 1 9 9 1 ). 151 Id

. at 1 3 59

. 152 E X ONE RA T E D BY S CI ENCE , su pra n ote 4 1 , at 6 5 (“ Th e State’ s exp ert o n th e h air ex am in atio n

testif i edth at o n ly

1 in4 ,5 0 0 0 p erso n

w ou ldh av e co n sistent h airs w h en testedf o r 4 0 d if f eren t ch aracteristics. He o n ly testif iedb etw een

8 an d1 2 ch aracteristics, h ow ev er, an dco u ldn o rem em b er wh icho n es. Th e ap p ellate co u rt ru ledo n

J u ly 2 9, 1 98 7 , th at h is testim o ny co u p ledw ith th e p ro secutio n ’ s u se o f

it at clo sin g arg um en ts, co n stitu tedd en ial o f

a f air trial.”). 153 7 5 4 F. Su

p p. 2 d 8 9 (D. Mass. 2 0 10 ).



### 26

### detecting dog (Billy ), the court found the closing argument misleading. The “government’s closing argument . . . dramatically overstated Billy ’s significance.” 1 5 4 

### I n its summation, the prosecutor “placed special emphasis on Billy the dog, imply ing that she had alerted to one space to the exclusion of all the others — which was not the case. Billy had not been shown ‘all other’ areas.” 1 5 5 

### Defense counsel failed to object. For this and other lapses, the court found that the defense counsel rendered ineffective assistance. The ABA Criminal Justice Standards state that “[ i] t is unprofessional conduct for the prosecutor intentionally to misstate the evidence or mislead the jury as to the inferences it may draw.” 1 5 6 

### The same rule applies to the defense. 1 5 7

154 Id

. at 9 5

. See a l so Mitch ell v . Gib so n , 2 6 2 F.3 d1 0 3 6 , 1 0 6 4 (1 0th Cir. 2 0 0 1 ) (Ex pert’ s m isco n du ct co m p o un d edb y

“ th e p ro secuto r, wh o m

th e d istrict co urt f

oun dh ad‘ lab o red ex ten siv ely

at trial to o b s cure th e tru e DNA test resu lts an dto h ig h lig h t [th e expert’ s] test resu lts,’ an dw h o se ch aracterizatio n

o f th e FBI rep ort inh is clo sin g arg um en t w as ‘ en tirely un su p p orted b y ev id en ce an d. . . m islead i n g .’ ”).

155 Id

. at 1 0 5. 156 ABA Stan d ard 5 .8 (a), su p ra n ote 2 2

. 157 Id

. Stan d ard4

- 7 .7

. 

### 27