Our judicial system rests on a premise so fundamental that most of us take it for granted: truth matters. Every witness in every proceeding raises their right hand and swears to tell the truth, the whole truth and nothing but the truth.  

In trial, direct examination presumes it and cross-examination tests it. Judges, juries, and arbitrators are asked to find it. The legitimacy of the result, whether of a bench trial, a jury trial or an arbitration, and even the outcome of a hearing of any kind, depends on the belief and expectation that truth will always prevail over falsehood. 

Expert testimony adds a second premise: genuine expertise has value. Courts permit experts to offer opinions because specialized knowledge can help the decision-maker understand evidence beyond ordinary experience. That privilege assumes more than intelligence or confidence. It assumes relevant training, reliable methods, and intellectual honesty. 

But what happens when the bases for these assumptions fail? What happens when an expert is caught lying?  

Until recently the answer seemed obvious. The witness was finished and his or her testimony was disregarded. 

I am concerned that this conclusion may be outdated. After dozens of trials and arbitrations across the country in recent years, I am concerned that that result is now far from assured. What happens when whoever is deciding the case does not regard the lie as disqualifying? 

When the Devastating Admission is Not Devastating 

Trial lawyers have long pursued the “Perry Mason” moment: the clean admission that collapses the witness’s credibility in front of the decision-maker. With an expert, the moment may involve some overlooked contradictory evidence, sometimes a fabricated academic credential, a nonexistent certification, a key calculation that is shown to be wrong, a test the witness claimed to perform but did not, a contradictory opinion offered in another matter or a scientific conclusion contradicted by the underlying data. 

Historically, such an admission could decide the credibility contest. Even jurors who could not independently evaluate the opinion as beyond their own education or experience understood that an expert who lied about the source of his authority or fudged the data or changed his or her mind depending on the client should not be trusted. The technical dispute suddenly had a simple moral center. 

I still encounter decision-makers who respond that way. But I have also seen a different response, particularly in arbitration. I have established that an expert with skimpy to non-existent qualifications gave false testimony about a material subject, only to watch the decision-maker treat the dishonesty as one factor among many.  

The witness remained in the case. Their opinions remained in play. The “mistake” or blatant lie was maybe assigned weight but not consequence, and was certainly not completely disregarded. 

My concern is that the unstated reaction seems to be that because nowadays “everyone lies,” lies no longer carry the same weight and lairs are not dismissed as such.  Essentially, dishonesty is not a line separating credible testimony from unreliable testimony. It is ordinary human behavior that enables the trier of fact to pick and chose between the lies and the truth depending on how they think the outcome should be. 

That represents a significant change in the way one should approach the risk of the final hearing. 

The Culture Enters the Courtroom 

Courtrooms, of course, do not operate in cultural isolation. The people who decide cases live in the same environment as everyone else: one saturated with political falsehoods, algorithmically amplified claims, partisan media, online performance, and declining confidence in institutions. Lies and blatant falsehoods increasingly dominate public discourse and while they may be recognized as such, such recognition is clearly not universal. 

In that environment, dishonesty can lose its moral force. A fabricated credential becomes résumé enhancement. A manipulated conclusion becomes advocacy. A refusal to acknowledge contrary evidence becomes strength. Some listeners distinguish between a lie about qualifications and the substance of an opinion, as though the character of the method can be separated from the character of the person applying it. 

The effect is not uniform. Many decision-makers remain deeply troubled by proven dishonesty. The critical point is that advocates can no longer assume that there is a shared reaction. The same impeachment may produce a juror’s outrage, indifference, rationalization, or even increased sympathy for a witness perceived as under attack. 

Gatekeeping Does Not Necessarily Solve the Problem 

Courts devote substantial effort to expert gatekeeping. There are well-known state and federal tests for the admission of expert testimony and if asked Judges examine qualifications, relevance, methodology, and scientific reliability. But the exclusion of a witness is often seen as a harsh result of such inquiry. The result is that the testimony of unqualified or marginally qualified “expert” witnesses who are not excluded is left for the factfinder under the familiar refrain that their lack of true expertise simply “goes to the weight” of the testimony. In arbitrations and bench trials, professional confidence in the factfinder’s own abilities wins out. In a jury trial, the hope is that the jury will do the job the court was supposed to do because that way there is less risk of reversal. 

The consequences are increasingly risky. Admitting the testimony may allow a dishonest expert to exploit the very complexity that made expert assistance necessary. Once the opinion is heard, confidence and repetition can compete with reliability. A technically weak conclusion may survive because the decision-maker lacks the tools, or the inclination, to reconstruct the science. 

Robust cross-examination, of course, remains the constitutional and practical answer. But it can be a last resort and advocates should consider bringing pre-trial challenges to experts even in marginal cases, to test the court’s reaction to the potential testimony even if admitted, and to be better prepared to deal with the consequences. 

Build a Case That Does Not Depend on Outrage 

Every trial lawyer should always investigate the credentials, prior testimony, publications, data, calculations, testing, and every material assumption of the other side’s experts, and their own. If an expert lies, those lies should of course be exposed. The record should never allow a false statement to pass unchallenged (leaving aside the strategy and timing of exposure). 

But in the modern, changed environment, one should be leery of assuming simple impeachment will accomplish a certain result by itself. 

The modern cross-examination should connect dishonesty directly to unreliability. It may not be enough merely to prove that the expert’s degree was fabricated. It is going to be necessary also to explain what knowledge the missing education was supposed to establish.  

It is not going to be enough to show that the expert misstated a test. It is going to be essential to demonstrate how the actual protocol undermines the conclusion.  

The same goes for-cherry-picked data. It is better to reconstruct the complete dataset and show how the excluded facts change the result. 

Faced with a skeptical or weak factfinder the goal should be cumulative proof. It may not be enough simply to establish the falsehood. It may make for longer examinations, ones that push the boundaries of repetition and time, but the object should be to make  continued reliance on the opinion unreasonable even for a decision-maker who is reluctant to condemn the witness. 

The affirmative expert presentation matters equally. A trustworthy expert should teach, not proclaim. Candor about uncertainty can be a competitive advantage. An expert who identifies limits, acknowledges contrary evidence, and explains how each conclusion can be verified offers the decision-maker a visible contrast between expertise and performance. 

Voir Dire Must Examine How Jurors Decide What is True   

In a jury trial, it all starts with voir dire. Traditional voir dire explores bias, relationships, prior experiences, and attitudes toward the subject matter. Those inquiries remain necessary. Complex cases also require attention to the juror’s theory of knowledge: How does this person decide what is true? 

In today’s atmosphere counsel should explore attitudes toward credentials, institutional authority, scientific consensus, confident speakers, and contradictory information. Can the juror revise an initial judgment after a source is shown to be unreliable? Does the juror regard a false statement as disqualifying, or as normal exaggeration? Does personal belief carry more weight than tested expertise? 

These questions should not become crude political screening. Party affiliation is an imperfect proxy for how anyone reasons. The objective is to understand the process by which a juror evaluates credibility, particularly when technical evidence cannot be independently verified during deliberations. 

Arbitrator Selection Requires the Same Discipline 

The issue is not confined to juries. Some of the clearest examples I have encountered arose in arbitration. After a carefully documented impeachment, an arbitrator declined to treat the expert’s falsehood as disqualifying and returned quickly to the competing technical narratives. 

That experience changed my due diligence. In expert-driven disputes, an arbitrator’s subject-matter knowledge is only part of the inquiry. Counsel should examine prior decisions and awards where available, published writings, speeches, professional affiliations, and demonstrated approaches to expert reliability. How does the arbitrator respond to methodological shortcuts? Does the arbitrator separate a witness’s dishonesty from the opinions built on that witness’s work? Is the arbitrator impressed by certainty or attentive to verification? 

A résumé can reveal whether an arbitrator understands the field. It rarely reveals whether the arbitrator will insist that the people explaining it tell the truth. 

The Stakes are Larger than Trial Strategy 

If experts may fabricate credentials or manipulate science without forfeiting trust, honest experts are placed at a disadvantage. If decision-makers treat lying as ordinary, cross-examination loses part of its corrective power. If factual accuracy becomes subordinate to confidence, identity, or ideology, adjudication begins to resemble the public discourse from which the legal system is supposed to offer refuge. 

Truth and credibility are not ornamental values. They are the infrastructure of adjudication. The oath matters only if violating it carries consequence. Expert status matters only if it reflects real knowledge and reliable practice. A verdict or award commands respect only if the process distinguishes evidence from performance. 

The trial lawyer’s task is therefore both practical and institutional. Catch the lie. Prove it with restraint. Explain why it corrupts the opinion. Build corroborating proof that does not depend on one dramatic moment. Select decision-makers with as much care as the forum allows. 

And never concede the premise that everyone lies, so no particular lie matters. 

If we give up on that, we give up the very thing that makes adjudication legitimate.