Common Expert Mistakes When Reviewing Trial Graphics

An expert signs off on a demonstrative the week before trial, calls it a fair depiction, and moves on to preparing testimony.

That sign-off is where many trial graphics start to fail.

Reviewing a demonstrative is a foundation check, not a design critique. It is the last practical chance to find whatever opposing counsel plans to spend twenty minutes on during cross. Here are the review mistakes we see most often and what a careful pass looks like instead.

Failing to Verify Anatomical Accuracy in Medical Illustrations

The usual failure here is one of sourcing rather than draftsmanship. The illustration is anatomically correct in general but wrong for this plaintiff in particular.

A stock cervical spine shows textbook disc spacing. The plaintiff’s MRI shows a C5-C6 herniation with foraminal narrowing on the left. When the medical-legal illustrations do not track the imaging in the record, the expert is being asked to adopt a picture of someone else’s neck.

Work the exhibit against the actual films and the operative report. Confirm laterality. Confirm the level. Confirm that any hardware in a post-surgical view matches what the surgeon documented placing. Labels deserve the same attention.

A mislabeled structure reads as carelessness to a jury and as an opening to defense counsel.

Overlooking the Technical Precision of Accident Recreations

Forensic accident reconstruction can break down at the input stage. The input people tend to trust most is often the one they understand least.

A typical light-vehicle event data recorder captures five seconds of pre-crash information, sampled twice per second. Under a NHTSA final rule that took effect in January 2025, the recording window expands to twenty seconds at ten samples per second. Most manufacturers must comply by September 1, 2027.

Until those vehicles are on the road, many cases will still contain only five seconds of data. So, anything an animation shows before that window begins is an inference based on other sources. Your expert should be able to identify them.

Police report conclusions are another weak point.

Courts frequently exclude an officer’s opinion about speed or fault, and any animation based on that opinion inherits all of its shortcomings, including issues no one identified during deposition.

Every element of the motion should be traceable to something the expert can defend independently, including scene measurements, crush profiles, photogrammetry from scene photographs, or downloaded module data.

Neglecting the Admissibility Standards for Digital Demonstratives

Federal practice changed here, and most review habits have not caught up. Rule 107 went into effect December 1, 2024, and it separates an illustrative aid from evidence.

An illustrative aid helps the jury understand testimony. It is not evidence; it does not go back to the deliberation room absent consent of all parties or a court order for good cause, and it must be entered into the record when practicable.

That distinguishes which standard the exhibit has to clear. An animation offered to illustrate a conclusion your expert already reached is one thing. A simulation offered as substantive proof of how the collision happened is expert output, and the 2023 amendment to Rule 702 requires the proponent to show it is more likely than not that the opinion reflects a reliable application of the method to these facts.

Deciding which of those you are building, before anyone renders a frame, is the single most useful question in the review.

Timelines land in the same analysis. One that compresses a six-month interval into the same visual space as a six-hour interval invites the argument that it misleads, and the admissibility of trial animations turns on exactly that kind of balancing.

Reviewing Visuals Too Late and Apart from the Testimony

Here are two habits that amount to one problem. The review happens after the graphic is final, with the expert reading a script rather than watching the exhibit run.

Late review turns every correction into a budget conversation. A change during storyboarding that takes an hour can take days once a medical animation is modeled, rendered, and lit. Discovery is also when the underlying material is still moving, and an exhibit built on a superseded report gets rebuilt.

The alignment problem is quieter and does more damage. Your expert testifies that impact occurred at roughly thirty-five miles per hour. The animation shows a vehicle that reads faster than that to anyone watching. Neither one is wrong by itself, and together they hand the other side a contradiction to work with. Run the demonstrative in real time while the expert delivers the accompanying testimony.

Mismatches in pacing, sequence, and emphasis surface immediately in that run-through, and almost never on paper.

Put the Review on the Case Calendar

The through-line is simple. The exhibit and the testimony have to arrive at trial saying the same thing, sourced to the same record, under the standard that actually applies to them.

Put the review on the case calendar instead of the trial prep week. Give your expert the underlying files alongside the draft. Ask which rule the exhibit falls under before anyone starts rendering. At Advocacy Digital Media, our team builds demonstratives with that review in mind, because we would rather answer the hard questions during storyboarding than hear them on cross.

If you have an exhibit that needs a serious accuracy pass, let’s talk about what it needs.