The AHRQ Patient Safety Indicators (PSIs) represent quality measures derived from administrative data. However, concerns about validity have led to increased scrutiny. This retrospective study analyzed all PSIs identified by standard algorithms over a 1-year period at a single academic medical center. A review team reversed 185 of the 657 PSIs initially identified, citing the two main reasons for reversal to be algorithm limitations and coding misinterpretations. The authors concluded that if PSIs continue to be publicly reported and carry financial implications for hospitals, the quality of administrative data and accuracy of PSI algorithms must be improved.