 Although base rate information should not be overlooked, paying excessive attention to it and ignoring other evidence leads to the so-called defense attorney’s fallacy. As before, suppose the prosecutor expert testifies that the defendant matches the traces found at the crime scene and there is a 5% probability that a random person, unrelated to the crime, would coincidentally match, so \(\Pr(\match\pmid \neg\source)=.05\). To claim that it is 95% likely that the defendant is the source of the traces, or in symbols, \(\Pr(\source\pmid \textsf{ match})=.95\), would be to commit the prosecutor’s fallacy described earlier. But suppose the defense argues that, since the population in town is 10,000 people, \(5\%\) of them would match by coincidence, that is, \(10,000\times 5\%=500\) people. Since the defendant could have left the traces as any of the other 499 people, he is \(\slashfrac{1}{500}=.2\%\) likely to be the source, a rather unimpressive figure. The match—the defense concludes—is worthless evidence.