Report Writing, Expert Testimony, and Courtroom Presentation
Domain 8 tests whether you can explain lock evidence clearly to a non-specialist and defend it under cross-examination. The report and testimony must show the basis, the method, and the limits of the opinion.
Report structure
- Purpose and scope; items received; chain of custody; examination dates and personnel.
- Methods and instruments; observations stated as facts; measurements; photographs referenced by number.
- Findings and opinions, each tied to observations. Use a conclusion scale and state limitations.
- Distinguish 'consistent with' from 'identified as.' Avoid advocacy language and unexplained jargon.
- Keep drafts and notes; reports are discoverable. A reviewer should be able to reproduce your reasoning.
Testimony
- Qualify your training and experience accurately. Explain the examination sequence and why alternative explanations were considered.
- On direct, give the opinion and its basis. On cross, concede what the evidence does not show; do not argue with counsel.
- Use demonstratives only if they accurately depict the evidence and are authenticated. Explain magnified images and scales.
Worked example
Your report says a plug-face mark is 'consistent with a picking attempt but not diagnostic.' On the stand, you explain that the mark could also come from key insertion, that no pin damage was found, and that the lock operated with its key. You do not upgrade the opinion under pressure. That consistency between report and testimony is what survives cross-examination.
Traps
- Offering an opinion beyond the examinations performed.
- Using 'unique' or 'match' without a defined comparison.
- Hiding limitations or negative findings.
- Testifying from memory without notes or report.
- Becoming an advocate for the retaining side.