It is unclear whether public reporting of hospital and physician performance has improved outcomes for the conditions being reported. We studied the effect of intensive public reporting on hospital mortality for 6 high-frequency, high-mortality medical conditions. Patients in Pennsylvania were matched to patients in other states with varying public reporting environments using propensity score methods. The effect of public reporting was estimated using a difference in differences approach. Patients treated at hospitals subjected to intensive public reporting had significantly lower odds of in-hospital mortality when compared with similar patients treated at hospitals in environments with no public reporting or only limited reporting. Overall, the 2000-2003 in-hospital mortality odds ratio for Pennsylvania patients versus non-Pennsylvania patients ranged from 0.59 to 0.79 across 6 clinical conditions (all P < .0001). For the same comparison using the 1997-1999 period, odds ratios ranged from 0.72 to 0.90, suggesting improvement when intensive public reporting occurred.