Harvard management guru Robert Behn examines how government leaders use PerformanceStat—a focused effort to exploit the power of purpose and motivation, responsibility and discretion, data and meetings, analysis and learning, and feedback and follow-up—to improve their organization’s performance. It started with the NYPD’s CompStat, gained further currency with Baltimore’s CitiStat, and continues to build steam. Behn tells the PerformanceStat story and reveals it potential—and its limitations.