The first step to critiquing an expert report on damages involves reviewing the author’s credentials and qualifications.
The Rules of Civil Procedure stipulate that it is the expert’s duty to provide opinion evidence that is related only to matters that are within the expert’s area of expertise. It therefore makes sense to conduct a thorough review of the expert’s area of expertise. I suggest obtaining and reviewing the author’s curriculum vitae, or CV, which should be attached to the report as an exhibit.
According to The Litigator’s Guide to Expert Witnesses,
"A critical review of the opposing expert’s resume is the most often overlooked but wonderfully useful source of cross-examination ammunition. An expert may have carefully reviewed the available information, critically reviewed the literature in the area, meticulously arrived at his opinion and artfully drawn his conclusions, but if he padded or fudged his resume he will be destroyed on cross examination." 
A summary of some questions to consider while reviewing the author’s CV is as follows:
- What training and education has the author obtained? What professional designation(s) does the author have (e.g. CA, CBV, IFA, etc.)?
- What professional standards must be followed in light of those professional designation(s)? For example, Chartered Business Valuators (CBVs) are required to follow the professional standards of the CICBV for Expert Reports (https://cicbv.ca/practice-standards/)
- What experience does the author have? Does it include loss quantification, valuation, accounting, statistics, industry, etc.
- Has the author provided expert testimony before? If so, what was the outcome?
- What publications and/or speaking engagements has the author prepared/presented? Are there any inconsistencies between his/her present opinion and those prior writings?
I was once retained by the defendant in a breach of tender matter (with respect to a construction project) to review the plaintiff’s expert report with respect to a claim for lost profits. The plaintiff’s expert report was prepared by a Chartered Accountant that did not appear to have any specific training or experience with loss quantification.
The plaintiff’s expert report quantified lost revenues as a result of the breach but did not take into account a profit margin on the revenues. As a result, the costs that would have been incurred to generate the lost revenues were disregarded. This was a serious deficiency which led to a significant overstatement of damages. Our responding report highlighted this as one of our major concerns with the conclusions contained in the plaintiff’s expert report.
I suspect that the lack of training and experience in damage quantification may have contributed to the quality of this expert report, including the reasonableness of its findings. This case never did proceed to trial as the parties ended up settling the matter out of court for much less than the plaintiff expert’s assessment. However, this case illustrated the importance of reviewing the author’s credentials and qualifications in critiquing an expert report.
1. The Litigator's Guide to Expert Witnesses, Mark J. Freiman and Mark L. Berenblut, 1997, page 41.