Expert opinion inadmissible in federal court

A reader sends this story:

The 7th Circuit U.S. Court of Appeals, in a 3-judge panel that includes the eminent Richard Posner, has ruled for the second time in case that began in April 2006 when two public high school students were prevented from wearing anti-gay T-shirts during a pro-gay festival called the Day of Silence.

As we learn on pages 11 and 14-16 of Posner's 17-page opinion, the school defended its decision to silence the students' free speech by presenting an expert opinion to show how harmful and disruptive their anti-gay message was. The expert had a Ph.D. in sociology and was a "professor of family and consumer sciences."

Posner granted the expert's expertise, but then showed that his 38-page report was so lacking in actual analysis that it failed to qualify as expert testimony under the Federal Rules of Evidence. Posner wrote: "Dr. Russell is an expert, but fails to indicate, however sketchily, how he used his expertise to generate his conclusion. Mere conclusions, without a “hint of an inferential process,” are useless to the court."

Most of the child custody evaluations would be inadmissible under the federal rule, FRE 702. The ones that I have seen show no hint of an inferential process. They don't cite any expert knowledge or explain any reasoning. They just recite some data gathering, and generate a conclusion. Any court that relies on such a report is acting contrary to what courts are supposed to do. Judge Posner agrees with that, anyway.