How New York Became Safe: The Full Story

A citywide effort, involving many agencies and institutions, helped restore order.

....By the early 1990s, these highly visible successes, especially in the subway, had begun to express themselves politically. Better than any other politician, Rudy Giuliani understood the pent-up demand for public order and built his successful 1993 run for mayor on quality-of-life themes. Once in office, he appointed Bratton, who had orchestrated the subway success and understood the importance of order maintenance, as New York?s police commissioner.

Under Bratton, the NYPD brought enormous capacities to bear on the city?s crime problem?particularly Compstat, its tactical planning and accountability system, which identified where crimes were occurring and held local commanders responsible for their areas. Giuliani and Bratton also gave the force?s members a clear vision of the ?business? of the NYPD and how their activities contributed to it. In short, a theory previously advocated largely by elites filtered down to?and inspired?line police officers, who had constituted a largely ignored and underused capacity.
http://www.city-journal.org/2009/nytom_ny-crime-decline.html