The culmination of an expert’s work is the expert report.  The expert report represents the final written product of the expert and serves a number of important purposes.  First, it documents the methodology and work of the expert, thereby outlining for counsel what work the expert has undertaken, what processes were used and what conclusions were reached.  Second, it forms the basis of direct and cross examination.  As a prosecutor, I have led and cross examined expert witnesses many hundreds of times.  A well written report often forms the blueprint for the expert’s testimony.  Third, it allows other experts the ability to evaluate the work that has been performed and assists in a critical review as to the soundness of the conclusions reached.  Fourth, an expert report is required as part of the disclosure and discovery process.  Finally, a well written report will be of considerable benefit to an expert witness preparing to testify and while testifying.  Think open book exam!

Expert witnesses have a positive obligation to document their work so that their conclusions can be properly evaluated.  Despite this obligation, some agencies insist that their experts write very brief reports.  That administrative requirement does a disservice to the expert whose work is going to be evaluated by other experts and who has to testify.  There is a misperception that the less an expert report contains, the fewer questions there will be on the witness stand.  That has not been my experience.  I have found that robust, well written reports often result in limited or no cross examination and not infrequently, a stipulation or admission of the expert’s evidence without the need to testify.

While a report that is too brief should be avoided, so too should a report that is too lengthy and too detailed.  Essential information should form the basis of the report.  More esoteric or unnecessary details can be contained within an appendix or bench notes.  Such details may result in avoidable cross examination and a distraction from what should be the true focus of the expert’s evidence.

An expert report should demonstrate organization, clarity and competence.  The following content should be covered in a logical and linear format:

Administrative Details

• Name, official title and business address of the expert
• Contact information of the expert
• Case identification information
• Signature of the expert
• Date the report was issued
• If the report is not a final report, it should be noted as an interim report

Work Request

In this section, the expert should set out how and when he/she became involved in the case.  This should include who engaged the services of the expert and, importantly, what information was provided about the case itself.  This will be explored further in a later post about expert witness bias and how to counter that spectre.  Also included in this section would be all exhibits, media, documents, etc. that the expert was asked to consider or examine.

Exhibit or Scene Examination

This section should contain details of the full examination of the exhibits submitted or scenes attended (or both).  This will include all measurements, data and other information gathered from the exhibits or the scene.  Often, this is the longest section of the report and will include photographs.

Data Gathered from Other Sources

On occasion, an expert may request or obtain information beyond what was initially provided.  For example, a forensic video analyst may be asked to perform a comparison between questioned images of a suspect, vehicle or other object and known images and that will necessitate a return to the scene to gather additional video images to be used in the comparison process.  Or a bloodstain pattern analyst may conduct laboratory experiments in order to determine the amount of blood that was found at a scene.  Or a collision analyst may undertake dynamic testing of a vehicle as part of the testing process.

Analysis of all Data

Once all of the exhibits and scenes have been examined and data gathered from other sources has been collected, all of this information must be analyzed with a view to answering the question(s) posed of the expert at the outset.  It is here where the expert sets out the methodology that was followed and the scientific principles that have been applied.  In colloquial terms, this is where the math is shown.

Conclusions

Every expert report must have a conclusion, even if the conclusion is inconclusive.  The expert must set out what conclusions have been reached as a result of all of the work that has been undertaken.  The conclusions should be clear and fully justifiable, based upon the data gathered.

Expert reports are primarily read by investigators and attorneys.  Occasionally, they may be read by a judge and sometimes by jurors.  It follows that even the most complex subjects have to be presented in a readable, intelligible and communicative manner.  It takes considerable time and effort to write a proper forensic report but it is part of an expert’s professional obligations.  An expert may not testify for years after authoring a report in some cases.  The time put in up front will pay off in the end.  Experts play an important role in criminal and civil litigation.  As part of that role, the expert is given an opportunity to write the screenplay for his/her trial performance so why not write one that assists the expert on the witness stand.