Top Trial Preparation Mistakes by the Defense

The most costly defense trial preparation mistakes are predictable, preventable, and entirely within the control of the defense team. For example, when key witnesses have not reviewed their own depositions, trial testimony preparation is rushed into a single cram session, or there is no structured questioning plan, and decision-makers refuse to invest in research and preparation, the result is avoidable exposure. These simple but critical defense trial preparation mistakes can be avoided through disciplined planning that protects against nuclear verdicts.

What is the core problem behind trial preparation mistakes?

The core issue is not trial skill; it is a lack of holistic preparation. Defense teams are still cutting corners in the two areas that most affect juror decisions: witness performance and case valuation strategy. Legal teams that don’t devote the appropriate time and effort in witness testimony effectiveness and scientifically-valid jury research in preparation for trial, dramatically increase the risk of poor litigation outcomes. Particularly when the plaintiff’s side is consistently investing their time fine tuning their narrative, visuals, and witness testimony by gathering juror feedback, the risks are even more magnified.

Mistake 1: Unprepared Key Witnesses

One of the most common and damaging mistakes in defense trial preparation is failing to ensure that key witnesses review their depositions thoroughly, well before trial. When a witness is unfamiliar with the existing record, they risk contradicting themselves on the stand, which can lead to impeachment and a loss of credibility. 

Prior to working with litigation psychology consultants for witness training and preparation, defense attorneys should ensure the witnesses have thoroughly reviewed all key documents, exhibits, and their prior deposition testimony well before engaging the consultant for training sessions.

Mistake 2: Don’t Treat Trial Witness Preparation as a Half-Day Event

Trying to compress serious trial testimony preparation into a single afternoon is one of the most damaging mistakes in defense trial preparation. Trial preparation, particularly for high-exposure cases, requires at least two dedicated days with litigation psychology consultants, plus separate witness/attorney sessions. The goal of witness training is to condition behavior under hostile questioning, rehearse adverse examination and rehabilitation, and stress-test the witness in realistic conditions to prevent breakdowns on the stand.

When this prep is crammed into a last-minute session, witnesses don’t get the required practice time and will default to bad habits, long, meandering answers, volunteering unnecessary information, defensiveness, or attempts to out-argue plaintiff’s counsel. To properly train the witness, start preparing 4–6 weeks before trial and use booster sessions closer to the trial date to develop durable, automatic behaviors that hold under pressure.

Mistake 3: Failing to Build Trust

One primary reason witnesses seem to ignore the preparation techniques they receive from their attorneys is that there is no authentic trust between the witness and the legal team. In the worst-case scenario, witnesses revert to what they “think works” and completely disregard the prearranged strategy, which can lead juries to dislike them and penalize the defense.

It is dangerous to assume automatic buy-in of witnesses in the stressful environment of trial preparation. Defense teams must take the time to get to know the witness as a person, understand and empathize with their concerns, and always explain the reasoning behind each behavioral direction and guidance. 

Defense counsel must make time for any required explanations. When witnesses trust their attorneys and the process, they will follow direction and avoid freelancing on the stand. When they do not trust their legal team or their process, all prior preparation risks becoming theoretical.

Mistake 4: “Winging It” Instead of Disciplined Mock Questioning

Entering preparation sessions without a strict script of cross-style questions is another common mistake in trial preparation. Informal walkthroughs are conversations, not preparation.

Three elements are necessary for adequate preparation: a comprehensive simulation of the plaintiff attorney’s demeanor and attack posture, a long-form, realistic set of adverse questions, and deliberate attempts to incite “rogue” behavior during preparation rather than during the trial. Failure during the training is the goal. By causing the witness to fail during prep, they are able to identify their gaps and, once corrected, won’t repeat those same errors at trial. 

Attorneys must utilize their own case expertise and model venue-specific and counsel-specific tactics when preparing witnesses during mock questioning. Failing to take as realistic an approach during preparation as possible will result in a witness who has never truly been tested before taking the witness stand.

Mistake 5: Don’t Assume the Settlement

Plaintiffs are no longer backing down. Settlement demands now routinely double or triple before trial, often accompanied by aggressive “take it or leave it” tactics. Delaying trial preparation on the assumption that a case will settle is a strategic error. 

The defense teams that avoid nuclear outcomes take the opposite approach: they begin witness preparation months in advance, conduct multiple, early rounds of jury research, and operate under the expectation that the case will go to trial. 

Thorough and data-driven preparation means even inflated demands are met with confidence, not concessions. When preparation is rushed or incomplete, plaintiffs have every incentive to push the case forward to trial.

Mistake 6: Refusing to Invest in Research and Preparation

One of the most serious mistakes in trial preparation is treating scientific jury research, witness preparation, and voir dire strategy as optional “extras” instead of core risk-control tools. 

Cases that invest in repeat mock jury projects, early witness preparation, and expert voir dire strategies are significantly better positioned for a defense verdict or more reasonable damages awards than those that do not.

On the other hand, a catastrophic verdict often includes predictable failures. Neglecting jury research and comprehensive witness training as a way to “save litigation costs” on the very tools designed to prevent nuclear outcomes is not cost savings; it is cost shifting from a controlled, science-based preparation spend to uncontrolled verdict exposure.

Mistake 7: Entering Trial Without a Defined “Win” or a Counter-Anchor Strategy

Successful defense teams define a win before trial, using research and data to establish a realistic verdict and damages range. Rather than relying on optimism, they enter the trial with a deliberate counter-anchoring strategy that begins in voir dire. This involves preparing jurors to expect an inflated number from the plaintiff and explaining the defense’s duty to challenge it. 

Avoiding or improvising numbers late in the process undermines credibility. A consistent, well-framed defense number or expectation helps jurors recognize unreasonable demands and align verdicts with the evidence, especially when supported by credible witnesses and science-based jury research.

Improve Trial Readiness with Courtroom Sciences

Don’t wait until the last days before trial to prepare key witnesses and strategies. Last-minute preparation and lack of investment in research and training leave witnesses exposed and significantly increase the risk of a nuclear verdict.

Courtroom Sciences helps attorneys efficiently navigate litigation by providing psychological expertise, science-backed data, and expert support for all phases of litigation. Learn how CSI’s litigation consulting experts can improve outcomes for your next case. 

Speak with one of our experts to get started.

By Courtroom Sciences, based on insights from the Litigation Psychology Podcast, Episode #99 – Trial Preparation, Part 2