New York's Police Department has gained much renown for its Compstat crime-reporting system, which has been emulated in police departments across the country and overseas. It has helped police to pinpoint criminal activity and to reduce reported crimes dramatically. But, with careers in the NYPD and City Hall made or broken based on the numbers, there is reason to suspect that some portion of the drop in the crime rate is more like crime fiction. I've made it my business to report on this (and this) over the years. I am pleased to see that The New York Times is doing so in a front-page story, City Keeping Minor Crimes under Radar.The crime statistics that elected officials and police brass know and love - the ones that have dropped so much since the early 1990s - are for seven categories of major offenses, including felony assaults, grand larceny, robbery, homicide. But, as the article notes, the NYPD has refused since 2003 to release statistics for lower-level offenses such as misdemeanor assaults, stolen property, and so forth.Why? The NYPD gives a tortured explanation in The Times about why it is unable to come up with this data, which it routinely reported to the state until 2002. It blames computer problems. But I would venture the real reason is that while the department was trumpeting the news that serious assaults had fallen sharply - by one-third between 1995 and 2002 - it wanted to divert attention from the fact that the number of simple assaults stayed around the same during that period. This pattern suggests that complaints about serious crimes were being downgraded to lesser ones. The refusal to release data for lesser crimes after 2002 certainly raises the suspicion that the discrepancy has continued or even enlarged.I've filed a variety of Freedom of Information Law requests for updated information, but the NYPD flouts this law and refuses to turn over the data I ask for. It took three years to get a decision on one of the requests.Meanwhile, a police officer named Adrian Schoolcraft secretly taped his roll calls and produced startling evidence of how manipulated the crime data were in his precinct. A remarkable series of articles by Graham Rayman in the Village Voice earlier this year told the story. Schoolcraft managed to document what I had heard from a number of police officers I know; rank-and-file police detest what's being done to manipulate the crime data, and their union in the past spoke out on the issue.The larger story behind this is that data, while useful, should not be idolized. And yet the idolization of data continues to expand, especially to evaluate education, but in many other areas as well.