The National Archive of Criminal Justice Data has raw data freely available (you’ll need a login) to hundreds — thousands? — of studies and publications related to criminal justice. One of the studies that has caught my eye is the “Evaluation of the Phoenix, Arizona, Homicide Clearance Initiative, 2003-2005”.

According to the introduction to the data, the study’s goal was “to conduct a process and outcome evaluation of the Homicide Clearance Project in the Phoenix, Arizona Police Department. The primary objective of the Homicide Clearance Project was to improve homicide clearance rates by increasing investigative time through the transfer of four crime scene specialists to the homicide unit.”

Phoenix studied their homicide investigation processes in great detail in order to understand how to improve them. And then they put the data online.

I haven’t read the full report, but looking through the raw data highlights what an important factor manpower allocation can be on solving murder cases. More investigators and more patrol officers dedicated to working homicides generally meant more as shown in the below to scatter plots of patrol officers per witness (left) and investigators per witness (right).

Solving murders is difficult and complex, but there does seem to be somewhat of a relationship between the number of officers deployed to the scene and the number of witnesses found.

The data also shows whether a case was open or closed, and the below chart shows pretty clearly that closed cases had more investigators, more patrol officers, and more witnesses than open cases.

Case Status Phoenix

This analysis is not meant to serve as an academic review of a decade old program, rather the point is to highlight just how important dedicating human resources can be to solving NOPD’s burgeoning homicide clearance problem.

Adding more officers to the problem isn’t the solution, but it’s certainly a step in the direction of a solution. And if looking through the Phoenix data taught me anything it’s that not only are more good detectives needed but more good patrol officers are also needed to help work these crimes.