Today the Dallas Court of Appeals reversed a sexual assault of a child conviction. The case is Wiseman vs. State. This case highlights the limits of expert testimony on the issue of honesty. Basically, an expert can't offer an opinion that certain groups of people lie, or certain groups tell the truth.
The expert testified that only 2% of children make up sexual assault allegations, and that most of those false allegations are from child custody cases. Fortunately, even in convict-at-all-Texas we don't allow trial by statistics.
What's the law on sexual assault experts? From the opinion-
Texas law is settled that an expert cannot give an opinion as to whether a person-or a class of persons to which the complainant belongs-is truthful. Yount, 872 S.W.2d at 712. "An expert who testifies that a class of persons to which the victim belongs is truthful is essentially telling the jury that they can believe the victim in the instant case as well." Id. at 711. This kind of testimony does not assist the jury as rule 702 contemplates. Id. Indeed, as we said in Wilson, such testimony "did not aid, but supplanted, the jury in its decision on whether the child complainant's testimony was credible."