What explains the way in which jurors cast their first vote in a criminal trial, before the dynamics of the deliberation process take over? Analysis of 3,000 jurors in criminal trials in four major metropolitan areas indicates, consistent with prior research, that jurors pay great attention to the evidence. The stronger the evidence against the defendant, the more likely the juror is to vote guilty. We also find that jurors dislike police duplicity. Police officers who give unbelievable testimony will, all else being equal, push jurors toward a first vote of not guilty. Beyond that, our conclusions are specific and limited to a particular jurisdiction. A juror's beliefs about the fairness of the law or the harshness of the consequences of conviction make a difference in some jurisdictions under some circumstances, but not in other jurisdictions under different circumstances. We also find that African-American jurors in the District of Columbia sitting on cases involving minority defendants charged with drug offenses are, unlike jurors in other jurisdictions, less likely to vote for conviction on the first ballot (but not on the final one) compared to white jurors. Our results therefore highlight the importance of analyzing juror behavior at a more local level. Analyzing juror behavior at the aggregate level can conceal important local variation.