In the open data world, crime statistics are an important data
set. But, I have had some recent thoughts about crime
statistics which I would like to share.
Where do crime stats come from?
When I worked in that field, we had 3 systems in which we could
pull from – CAD, ARS and RMS. The systems worked as follows:
- CAD – are the calls for service. They were the most
current. But also, the crime type and information is the most
- ARS – These are reports that have been approved by an
officer and a supervisor(SGT). They are probably 1 to 2 weeks
out from the data of occurrence but are more accurate than CAD.
- RMS – These are reports that have been approved by records
employees and are the final, authoritative source of
information. These are possible a month old but are the most
As you can see, as time increases (we get further away from the
data of occurrence) the accuracy of the data associated with
the incident increases. Do you know which source the data set
you are using comes from?
This dataset contains the block location, case number
description and date of calls for service received by APD
that have been entered into the case management system and
approved by a supervisor.