Role of Scientific Method
in Public Policy Analysis
The Admissibility of Scientific
Evidence & Expert Witnesses
Varying Roles of Expertise
Legislation
Regulation
Litigation
Some Rules of Evidence
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Burden of proof & going forward
Relevance (to proposition)
Material (to issue at trial)
Hearsay exclusion & exceptions
• Business records, admissions, excited/dying utterances,
learned treatises …
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Best Evidence
Foundation: chain of custody
Other issues: criminal vs. civil, demonstrative,
judicial notice, impeachment,
confrontation/cross-exam & impeachment,
privelege …
Frye v. U.S.
Facts: 1923 2nd degree murder defense
offered expert to validate polygraph (blood
pressure-type) to exonerate defendant
Issue: What constitutes acceptable scientific
methodology to support expert testimony?
Holding: methodology underlying expert’s
evidence must be sufficiently established to
gain general acceptance in the particular
field
Frye v. U.S.
Frye general acceptance standard:
1. ID witnesses’ expertise in particular
field of science (education,
experience, contribution)
2. Determine whether expert’s
methods, theories & conclusions
satisfy general acceptance standard
Frye’s Implications
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Experts & scientific evidence excluded
unless expert qualified & testimony
satisfies general acceptance standard
Consensus of scientific community
required from peer review, pubs, criticism,
replication & reliability
Novel theories generally inadmissible
Judges relieved of deep analysis
Still valid standard in dozen states +/- &
continuing role in ’90s Daubert trilogy
Daubert v. Merrell Dow Pharma
Facts: Admissibility of 8 experts re-analysis
of epidemiological statistics as well as
animal & toxicological studies linking
Bendectin to birth defects
Issue: Are un-published expert analyses
admissible to show scientific causation?
Holding: reversed & remanded
Discussion: Frye rejected as sole
admissibility standard
Daubert v. Merrell Dow Pharma
Discussion: Judges must serve as ad
hoc admissibility reliability gatekeepers
 Is/can the science (be) tested?
 Subjected to peer review & publication
 What is known or potential error rate
 What is general acceptance (FRYE
lives) in relevant scientific community?
GE v. Joiner
Facts: GE electrician claimed lung cancer
resulted from jobsite PCB exposure
Issue: Is there analytical gap? YES
Holding: Expert’s conclusions & basis for
judgment must flow rationally from
purported methodology
Discussion: Expert’s insistence of causation
must be demonstrated with full explication
of logic, premises, studies, links shown in
studies: expert report susceptible to
support, explanation & defense
Carmichael v. Kumho Tire
Facts: Kumho blewout on Ford mini-van causing
overturn, death, injuries
Issue: Tire failure analysis sufficiently scientific
Holding: Trial judge excluded tire expert testimony
Discussion: Daubert applies to all experts
(technical, specialized knowledge) not just
“scientists;” increases judge’s scrutiny of experts
& methodologies; Daubert applies more flexibly –
not checklist; appeal of trial judge allowance
tested by “abuse of discretion” not “de novo” std
Trilogy Observations
Jury, not judge, must evaluate
conflicting expert & scientific evidence
 Judge is gatekeeper on rigor, crossexam, judge instr. & BofP also key
 Formal Daubert hearings not always
necessary
 Kumho too difficult for judges to
distinguish scientific from other
technical disciplines
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Some key emerging expertises
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Statistics, multiple-regression
Survey Research
Estimation of economic damages
Epidemiology
Toxicology
Engineering practice
DNA
Medical diagnosis & treatment
Environmental & workplace exposure
Employment issues
(@ least) Three Challenges
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Dissemination of Tort databases
ventilates experts’ views
Expertise assumes varying roles in
law & regulation
Reform of tort/product
liability/regulation could undercut
many key
#1: Dissemination
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National Tort Data Project
• NAS/NRC funded, field & empirical
methods
• Database for defensive use by AGs, DOTs
• Traditionally rare & reputational: only
secret files from insurance & class action
• Major push to profile experts
• Increasingly well-organized, exhaustive
Largely intended for risk mgt feedback
 Grave fears that plaintiff’s bar might
access
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Dissemination
Scrutiny of prior testimony arms Xexam to effectively depose, disparage
st testimony
 Increases stakes of 1
 Every negative X-exam impacts future
fees
 Eventually IDs potentially adverse
experts
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• Reduces ranks of all experts
• Isolates ideological foes
• Polarizes experts, not unlike plaintiffdefense bar
#2: Varying Roles of Expertise
Legislation
Regulation
Litigation
#3: Reform Could Undercut Need
for Expertises
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Continuing drive towards reform of tort,
product liability & regulatory programs
likely to reduce needs for well-paid
experts (also: plaintiff’s bar, defense bar,
judges, catastrophic insurance coverage)
80s tort crisis is an instructive history
• Deserves serious scholarly focus!
• Competition lowered premiums, investment
returns covered payouts until stk mkt dive
• Coverages w/drawn
Tort Law is a Pendulum
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19th Century: many limiting
principles prevented liability
• Fellow servant, proximate cause, privity
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Post 1920 torts & product liability
experienced steady expansion
• New liability theories
• New tortfeasor duties
• ID new risks
More 20th Century Expansion
Recognize scientific causal links to
injury
 New forms of injury
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• Economic damages
• Non-economic damages
• Economists forcing a merger?
New theories of injury valuation
 Public opinion expanding
acceptability
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Focci of Tort Reforms
Plaintiff
 Injuries
 Defendant
 Duties
 Counsel
 Forum
 Proofs
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Future of Reform?
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Slow, pragmatic identification of liability
risks & connection to a litigation process
Significant federalism overtones
• Preemption: “It only takes 270!”
• Conservative S.Ct. states righters
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Many reforms invalidated in 1990s
• Over 1/2 States Courts Invalidate Some Reforms
• State & Federal Constitutional Bases for Invalidation:
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Right to remedy, court open
Due process, equal protection
• Most Vulnerable Reforms: Damage caps, statutes of
repose, collateral source rule, specific industry
exemptions