The former [NYPD] captains spoke of an unrelenting, often unethical pressure to manipulate crime statistics. In addition, the professors studied [NYPD] police and health data and found weird divergences. [NY] City hospital data shows a 90 percent increase in emergency room visits for assaults from 1999 to 2006. But [NYPD] police data for the same period records a nearly 50 percent decrease in assaults.