Sort of a weak article - no stats. It'd be much more useful if it simply stated things clearly. Something like "90% of reports are for Xs, while only 40% of the crimes are by Xs". Or even better, "out of n Xs, only m commit a crime". Then show incorrect biases there. (The only stat I saw was % of black population vs % of detainees being black - that's not so relevant without knowing actual crime rates. )<p>(Edit: I see why they didn't include this stat. According to [1], over 80% of suspects for various crimes were black. So that would explain why the police are pulling over a higher %, right? This still doesn't excuse base rate fallacy but sort of dismisses the one stat the article does provide.)<p>Or more usefully, provide better characteristics off which to classify. If race, gender, and clothing have no predictive power, demonstrate that and show what does.<p>Nextdoor could even build priors into the site, over time and help provide accurate predictions. After all, they have both the suspicious report info plus the actual crime info. Imagine if it would rate your post: "Based on your report of a male walking at 6am, the probability this is a criminal is 0.02%" That'd go a long way towards making people update internal models as well as making them look silly for using non-predictive characteristics. (Though if most crimes are committed by young males, it might be called out as ageist and sexist, but hey if that's reality...)<p>Plus you could grade individual users. So combining the base rate of crime, significant characteristics, and past performance of a user? "MaryX, given your past suspicious activity record, there's a 99% chance this post is incorrect."<p>Without this, all it takes is a busybody to report everything they see (and they can select on anything: race, gender, hair color, shoe size) and eventually get a correct hit. Then ignore the times they were wrong and point out how "see I reported this X and it was a thief!"<p>1: <a href="http://www.sfgate.com/bayarea/johnson/article/Oakland-crime-issue-goes-far-deeper-than-racial-5355633.php" rel="nofollow">http://www.sfgate.com/bayarea/johnson/article/Oakland-crime-...</a>