The method used to categorize an event in the criminal legal system is different for an incident, an arrest, and a case within the court system.
Incidents receive an intial classification by the Philadelpiha Police Department at the time of reporting, which may or may not reflect the reality of the event. When an arrest is made, the police recommend a set of charges that they believe the arrestee should be charged with. Ultimately, the District Attorney’s Office determines whether to charge an arrestee and what to charge that person with. The Dashboard uses incident classification to categorize incidents, police recommended charges to categorize arrests, and the actual charges brought in court to categorize the case from the time of charging and beyond.
The advantage of this system is that it allows users of the Dashboard to view incidents, arrests, and cases as they actually moved through the system. If an incident is originaly classified as an Aggravated Assault and the police recommended charges for Aggravated assault, the dashboard will reflect that even if the DAO ultimately disagreed and charged the case as a Simple Assault. Similarly, the dashboard will count that case as a simple assault for the purpos of court-related activity, like bail, case outcomes, and sentencing, rather than keep the original police category of Aggravated Assault. This system also allows for a more granular look at the system, breaking incidents categorized as, for example, Illegal Firearm Possession into its component offenses of Firearm Possession by a Prohibited Person and Firearm Possession Without a License.
The disadvantage of this system is that it limits the ability to track a set of incidents through the entire system. For example, an incident that was initially called a “Robbery/Gun” on the Incidents page could become an “Aggravated Assault” on the Arrests page, which could then become an “Attempted Homicide” on the Charges page. That means that it isn’t possible to use the dashboard to know, for example, what percentage of Robbery/Gun incidents lead to an arrest, and what the case outcomes for the subsequent cases are.
For the first two years of the Dashboard’s existence, we did the opposite: we used the original police classification of each incident to classify that case as it moved through the system. While there were advantages to this system, it distorted outcomes in the court system in a way that we believe was inaccurate.We feel that it is important to show the most accurate picture of the criminal legal system that can be understood at each stage of the process. We also feel it is the responsibility of the District Attorney’s Office to show the decisions we have made. We cannot go ‘back in time’ and reclassify incidents and arrests after a charging decision has been made without distorting history and presenting a false view of these stages. Given the constraints of our data, and for these reasons, we feel that categorizing each event at each stage allows for the most complete representation of the system available. For more information about this change, please read this data story.
The District Attorney’s Office does not have data on crime incidents in the City other than what is available to the public through the City of Philadelphia’s open data program. We use OpenDataPhilly’s Parts I & II Crime Incidents dataset to study crime events, many of which do not lead to arrests. This leads to a number of limitations:
We use ZCTAs in the downloadable sets for two reasons: