Don't Rely Too Much on Common Sense:

The Tenth Circuit just reversed the insider trading conviction of Joseph Nacchio, former CEO of Qwest. (Congratulations to my Mayer Brown colleague Andy Schapiro, who cofiled an amicus brief on behalf of the National Association of Criminal Defense Lawyers supporting reversal.)

The reversal stemmed from the trial judge's exclusion of economic expert evidence. Among other things, the trial judge concluded that the evidence would "invit[e] the jurors to abandon their own common sense and common experience and succumb to this expert's credential." The panel majority responded:

While economic analysis sometimes asks jurors to "abandon their own common sense," App. 3920, that is not a reason to deem expert testimony inadmissible. Armchair economics is not the way to decide complex securities cases.

Absolutely right.