Where does the data come from?

• Each morning by 9:30 AM, the Tucson Police Department and the City's Information Technology Department make available for download two files containing records of police events and incidents for the most recent 45 days. The records are extracted from the Police Department's computer systems, geocoded to obtain X and Y coordinates for the approximate location of the incident, matched to a neighborhood boundary layer and packaged up for download.
  
  After local processing, finalized web pages are uploaded to the public website, usually shortly after 10 AM. The data files typically include events and incidents that were reported as recently as just before midnight of the day before.

How reliable is the data?

• Police data used here covers the City of Tucson. It does not include data from Pima County, South Tucson, University of Arizona, Pima Community College, Davis Monthan AFB, Tucson International Airport, state, federal or other law enforcement agencies.
  
  Police incidents were screened according to definitions included in the local version of the Uniform Crime Reporting program of the U.S. Federal Bureau of Investigation. Police event and incident information is approximate and subject to change. This is particularly true of the most recent information.
  
  Data on reported and discovered police events and incidents is based on factors that change over time; therefore this data should be used with caution. Some factors affecting police data are:
  • Actual numbers of police incidents as interpreted through Uniform Crime Reporting rules, including record updates based on new information
  • Rate of reporting by citizens or crime victims
  • Time lags in completion of or automation of police reports
  • Neighborhood boundaries as included in geoprocessing tables
  • Special efforts of police to reduce crime (which may increase the amount of crime known to police)
  • Special efforts of victims to reduce crime, such as shoplifting prevention programs (which may increase the amount of crime known to police)
  • Data processing practices, including geocoding match rate
  • Changes in the law or in criminal justice system policies and practices

Did the updating work this morning?

• Some listings will not show any events or incidents from yesterday, making the viewer wonder whether the current file was updated this morning. No incidents may come from the fact that there were no police incidents in the neighborhood during the last 24 hours. Check other neighborhoods.
  
  Another reason may be that the update process did not work correctly. The program is set to send an administrative email message to the database manager when errors occur. It is also possible that a computer was down when the timed update process was to occur. The entire update process is repeated several hours later to allow for a downed computer.

What do the colors on the incidents mean?

• Incidents cleared by the initial officer as crimes (UCR codes 5-29) are shown with a pink background. The most serious crime types (UCR 1-4, homicide, rape, robbery and aggravated assault) are shown with a darker magenta background. UCR codes are here.

How can I contact you?

• This system was created by Donald Ijams. It is hosted by Harold Hallikainen, who can be reached at harold -at- w6iwi.org . Feedback and error correction information is most welcome.

Tell me about the columns on the listing.

• Location of Event or Incident

  • This is the street address from where the event or incident was reported and is most often where it occurred. The street number is masked to protect victims from harassment. This address is approximate as many incidents will have happened in the street in front of the house, or in the alley or in the parking lot. The incident may have nothing to do with the occupants of the nearest building.
  
  

• Date Reported

  • The date the event or incident was reported to or discovered by Tucson Police is shown here. This may not be the date the incident happened.
  
  

• Time Reported

  • The time the event or incident was entered into the Tucson Police computer assisted dispatch system or main database is shown here. This is not the time the incident occurred.
  
  

• Event Initiated As

  • Most often, as a result of the reporting party's telephone conversation with Tucson Police, the police service operator will enter a code that tells the dispatched officer what to expect. This information is only preliminary and does not reflect what the officer found.
  
  

• Officer Cleared Incident As

  • In some cases, after Tucson Police personnel complete their preliminary investigation at the scene, the primary officer will enter a computer code showing what was found. This code may be altered after follow up investigation occurs or after review by police records personnel.
  
  

• Reference Number

  • Each police event and incident receives a ten character reference number, to uniquely identify it in the records system. Use this number to refer to a specific case. Some events have no followup data; these records receive a reference number starting with an E.