Daubert, Rule 702, and
police practices testimony.

Fed. R. Evid. 702 puts four questions to every proffered expert: whether the witness is qualified by knowledge, skill, experience, training or education; whether the testimony will help the trier of fact; whether it rests on sufficient facts or data; and whether it is the product of reliable principles and methods, reliably applied to the facts of the case. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993) assigned trial judges the gatekeeping role: before an opinion reaches the jury, the court satisfies itself that the opinion is more than credentialed assertion.

Practitioners usually compress the inquiry into three words: qualification, reliability, fit. Qualification asks whether this witness, on this subject, knows something an ordinary juror does not. Reliability asks whether the method that produced the opinion can be examined against something outside the expert’s own say-so. Fit asks whether the opinion bears on a disputed issue in the case rather than floating above it.

Fit deserves more attention than it usually gets in police cases. An opinion grounded in generally accepted police practices helps the jury evaluate conduct it has no professional frame for: how officers are trained to approach a stop, what agency policy required, what national standards treat as accepted practice. An opinion that announces which party should win, or that conduct was unconstitutional, is not police practices testimony; it is a legal conclusion wearing an expert caption, and it draws the motion. Scope discipline is fit insurance.

Rule 702 challenges are decided on written motions more often than live hearings, which makes the expert’s report the main exhibit. A report built line by line from the record is the strongest Daubert posture an expert can hand counsel.

The method that survives inspection is not mysterious. It starts with the complete record: video, reports, witness statements, deposition transcripts, training files and agency policy, reviewed in full rather than curated for comfort. The record is then measured against identifiable, external standards: controlling case law such as Graham v. Connor, 490 U.S. 386 (1989) on use-of-force questions, the agency’s own written policy in force on the date of the incident, and the national standards, model policies and training curricula, from bodies such as the IACP, PERF and state POST commissions, that inform what generally accepted police practices are.

Three disciplines keep the method inside the gate. The analysis is anchored to what was known at the time, because Graham forbids hindsight. It is applied the same way in every case, whichever side retains the expert, so opposing counsel cannot show the method bending toward the client. And it stays inside the witness’s discipline: where the record raises medical, scientific, technical or human factors questions, qualified experts in those disciplines are deferred to, on the record.

• Every opinion is cited to the record it rests on: the page, the timestamp, the policy provision.
• Standards are identified by name, so the court can verify they exist outside the report.
• The same standards apply whether the retention comes from plaintiff’s counsel or the defense.
• Contrary evidence is addressed rather than omitted; an opinion that ignores half the record invites the motion.
• Conclusions stay inside police practices; legal conclusions remain counsel’s.

Counsel weighing Daubert exposure should ask a concrete question: has a court already examined this witness’s qualifications and method, and what did it say. For this practice the answer is on the record. Ruling on a motion to exclude Professor Gilbertson’s testimony in federal civil rights litigation in the U.S. District Court for the Western District of Washington, the court reviewed his qualifications and experience and allowed the testimony to proceed. The court’s ruling in Alvarez v. King County is reproduced in the judge’s own words under judicial recognition on the homepage.

The broader record extends beyond one ruling. Professor Gilbertson’s testimony has not been excluded at trial in any state or federal court, across an expert practice running since 2014 and more than 220 civil rights and criminal cases in 42 states and the District of Columbia. What that sentence claims, and what it deliberately does not, is treated in what never excluded at trial means.

For the qualification prong, the full CV and the testimony record go to retaining counsel on request, so the foundation exhibits for an admissibility fight are assembled before any challenge arrives.