The CHESS method of forensic opinion formulation: striving to checkmate bias.

Expert witnesses use various methods to render dispassionate opinions. Some forensic psychiatrists acknowledge bias up front; other experts use principles endorsed by the American Academy of Psychiatry and the Law or other professional organizations. This article introduces CHESS, a systematic method for reducing bias in expert opinions. The CHESS method involves identifying a Claim or preliminary opinion; developing a Hierarchy of supporting evidence; examining the evidence for weaknesses or areas of Exposure; Studying and revising the claim and supporting evidence; and Synthesizing a revised opinion. Case examples illustrate how the CHESS method may help experts reduce bias while strengthening opinions. The method also helps experts prepare for court by reminding them to anticipate questions that may be asked during cross-examination. The CHESS method provides a framework for formulating, revising, and identifying limitations of opinions, which allows experts to incorporate neutrality into forensic opinions.