94% Clearance Rate

You want to see how easy it is to manipulate statistics until the numbers start to scream? Look how they do it in Washington DC:

• For the past two months, D.C. Police Chief Cathy L. Lanier has touted the city’s astronomically high homicide closure rate — 94 percent for 2011 — and warned anyone contemplating murder in the District to think twice.

  “Your risk of being caught is pretty high if you commit a homicide in D.C.,” Lanier told The Washington Post in December.

Wow. They must have the best detectives in the whole world, right?

• But an examination of District homicides found that the department’s closure rate is a statistical mishmash that makes things seem much better than they are. The District had 108 homicides last year, police records show. A 94 percent closure rate would mean that detectives solved 102 of them. But only 62 were solved as of year’s end, for a true closure rate of 57 percent, according to records reviewed by The Post.

  D.C. police achieved the high closure rate last year by including about 40 cases from other years that were closed in 2011.

57% is still almost double Chicago's rate. But you can see exactly how data manipulation leads to a slightly skewed view of results and how the political structure can use the revised data to achieve a certain end.

Anyone want to bet what big city department is about to start torturing their own numbers to make sure a certain politician has a shot at a Senate seat, maybe even a presidential run?