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524–541.EXPERTTESTIMONY,
QUALIFICATIONS OFEXPERTS
Under the Federal Rules of Evidence and virtually all
state codes, expertise is defined by the nature and
scope of the proffered opinion. The basic issue with
regard to a qualifications assessment is whether the
witness has the background to support his or her
intended testimony. An expert must be qualified to
“assist the trier of fact.” But no strict tests or minimum
requirements apply to the assessment of qualified
expertise. The level of qualifications required varies
with the demands of the proffered testimony.
The Federal Rules of Evidence, for example, define
qualifications broadly, encompassing “knowledge,
skill, experience, training, or education.” In general,
courts interpret the main qualifications requirement in
relation to the expert’s claimed expertise and the
nature of the testimony. Hence, experts on medical
matters are expected to have medical degrees, appro-
priate certifications, and experience, but auto mechan-
ics or real estate appraisers might only need years of
experience and demonstrable skills. Professional
degrees or certifications, therefore, may be considered
by courts because they reflect the expert’s level of skill
or experience but are not formal requirements of the
rules. As a practical matter, courts typically consult the
experts’ respective fields for guidance regarding
what constitutes a “qualified” expert. Not all fields,however, have well-articulated standards, and many
subjects of interest to the law are studied by fields with
widely varying professional requirements.
Because an expert’s qualifications must be suffi-
cient to support his or her intended testimony, courts
regularly demand that experts possess certain minimal
degree requirements or professional certifications
before being allowed to testify. In a case presenting an
issue of medical causation, for instance, a court is
likely to require an expert to possess a medical degree.
Similarly, testimony regarding structural engineering
will typically be introduced through the testimony of
a structural engineer. In most jurisdictions, the ques-
tion of a particular expert’s qualifications is within the
discretion of the trial court and will not be overturned
absent a finding that the lower court abused its discre-
tion. Indeed, it is highly unusual for an appellate court
to reverse a lower court’s finding that a particular
expert passes or fails the qualifications test.
With regard to fields with highly formalized creden-
tialing requirements, courts tend to follow the respec-
tive field’s expectations regarding what it takes to be
“qualified.” This usually means that the courts mirror
the respective fields from which the experts hail. If, for
example, a field requires certification to practice the
expertise, courts tend to assume that party experts from
that field will possess the requisite certification. Experts
who fail to meet their own field’s qualifications
demands are presumed unqualified by most courts.
This, however, is a rebuttable presumption. Courts use
a field’s certification requirements as a guidepost for
judging expertise, not as a prerequisite to receiving an
expert’s opinion. In effect, therefore, a field’s certifica-
tion requirement constitutes a factor, albeit an impor-
tant one, in the assessment of qualifications.
Many expert fields, however, have no formal cre-
dential requirements, and the courts similarly follow
the field’s lead here too. Hence, medical experts usually
must have attained the M.D. degree at a minimum, but
experts on psychological subjects might possess a host
of degrees or even experience-based specialization. For
example, courts sometimes find experts with just a B.A.
degree, together with significant work experience, to be
minimally qualified to testify generally on subjects
such as the battered woman syndrome or child abuse
accommodation syndrome.
Although courts are typically permissive regarding
credentials when experts propose to testify on general
subjects in psychology, there are limits to this gen-
erosity. In particular, courts might require higher280 ———Expert Testimony, Qualifications of ExpertsE-Cutler (Encyc)-45463.qxd 11/18/2007 12:42 PM Page 280