Definition of Important Measures

  • Number of Incidents: Incidents are one or more offenses committed by the same offender or group of offenders acting in concert. 

  • Number of Offenses: Within each incident each distinct type of offense is counted once, regardless of the number of offenders or the number of victims.

  • Number of Crimes: This is the same as the Number of Offenses, with these exceptions:

  1. It is the number of victims of Crimes Against Person.

  2. It is the number of vehicles stolen when the offense is a completed Motor Vehicle Theft. 

  3. It is 0 for Justifiable Homicide (and Suicide in some states).

  • Rate Measures (e.g. Crime Rate per 100,000 or 1,000) are calculated by dividing the corresponding measure by the population in the selected Jurisdiction and then multiplying by either 1,000 or 100,000 depending on the measure selected.

  • Drug Quantity: A sum of the drug quantities provided, but only when a single value is selected on the Drug Measurement dimension (to avoid adding together data with different units).

How Hierarchies Work

  • Select individual members, all members at the same level (e.g. all agencies), or a member and all members contained within it (e.g. all agencies within a county as well as the county total)

  • Selections are all independent of each other. For example, a year total is the same regardless of whether or not individual months are selected.

  • Hierarchies are not necessarily additive, depending on the measure selected.  For example, a victim of robbery and murder will be counted against each offense, but will only be counted once when looking at the Crimes Against Person member on the Offense Type hierarchy.

Using Jurisdiction Dimensions

  • There are three jurisdiction dimensions in most cubes.

  • The Jurisdiction by Geography dimension can be used to select the state, the county or any agency within the county.   It contains other levels of geography in some states.

  • The Jurisdiction by Type dimension enables the user to select the state as a whole, agencies grouped together by type (State Law Enforcement Agency, Sheriff’s Office, etc.), or each individual agency. 

  • The Jurisdiction by Status dimension allows the user to select only agencies that are currently reporting NIBRS, excluding those that are defunct or are still reporting Summary.

Using Date Dimensions

  • There are dimensions for many of the dates being reported, such as Incident Date, Arrest Date, Summary Date, etc.

  • Each date dimension has a hierarchy that allows users to get year totals, monthly totals, daily totals (NIBRS only), etc.

  • There are also dimensions for Incident Date of the Week and Month, which allows the user to aggregate all crimes that take place on Fridays or during January across years.

Default Members

  • Every dimension has a default member, thus eliminating the need to make selections on every dimension

  • Default members are typically the “All” members, which means that no filtering is done based on this dimension.

  • Some dimensions have default members that cause some filtering to take place.  These are:

  1. Multiple Arrest Indicator - in the Arrestee Data and All Arrestee Data cubes.

  2. Incident Date - in all cubes except the Arrestee and All Arrestee cubes.


See Also: