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Standardizing the Display of IBR Data: Time and Date Variables

Additional Examples of Displaying Time and Date Variables

Time and date variables are used in many reports to show when various offenses are most likely to occur.  Different tables use different groupings; for example, days can be grouped into weekends and weekdays; time of day can be broken into 4-hour blocks; time of day can be broken into school hours, etc.

Examples of tables using time and date variables are presented below.  SPSS code is presented with each table.

The first table looks at the occurrence of juvenile firearm violence, comparing time-of-day categories in weekends and weekdays.

Example 1.  Time of Juvenile Firearm Violence
Produced by the South Carolina Department of Public Safety and the University of South Carolina in Juvenile and Young Adult Firearm Use in South Carolina, 1999.

  Weekend   Weekday
  Number Percent   Number Percent
Mid - 6:59 AM 36 22.5   83 15.3
7 AM - 7:59 AM 1 .6   9 1.7
8 AM - 11:59 AM 14 8.8   54 9.9
Noon - 2:59 PM 25 15.6   47 8.6
3 PM - 5:59 PM 16 10.0   111 20.4
6 PM - 8:59 PM 33 20.6   118 21.7
9 PM - 11:59 PM 35 21.9   122 22.4
           

TOTAL

 160 100   544 100


To create this table, time-of-day and day-of-week variables were grouped into categories.   Juvenile arrestees with an offense location code of school/college were selected.   A cross-tabulation table was then produced. 

View SPSS syntax with narrative for Example 1.   
Download SPSS syntax for Example 1.
Note: Please check that the variable names used in this syntax match the variable names in your data file.  If you need assistance, contact JRSA.
Download sample SPSS data to be used in this example.  
Download resulting SPSS data created by the syntax.  

The next table looks at the time of day robberies occur at various types of locations.

Example 2.  Time of Day of Personal Robberies by Type of Location
Produced by Brian A. Reaves, BJS, in Using NIBRS Data to Analyze Violent Crime, 1993.

    Time of Day (%)
Type of Location Number Midnight - 3:59 AM 4 - 7:59 AM 8 - 11:59 AM Noon - 3:59 PM 4 - 7:59 PM 8 - 11:59 PM
All 8265 24% 9% 7% 11% 18% 32%
Roadway 3444 26 9 6 10 17 32
Residence 1628 23 9 10 11 17 31
Parking Facility 739 22 9 7 11 17 33
Store 708 19 8 8 11 24 30
Office Building 438 18 10 7 12 21 32
Hotel, Motel 145 30 12 2 4 13 39
Bar, Night Club 117 46 6 0 2 15 32
Financial Inst. 106 8 7 17 12 14 42
Gas Station 104 27 15 8 8 14 28
Other, Unknown 836 22 9 8 14 18 29

This table was created by grouping time of day into 4-hour categories.  Robbery offenses were then selected.  Location was also grouped, and a cross-tabulation table was created.

View SPSS syntax for Example 2.  
Download SPSS syntax for Example 2.  
Note: Please check that the variable names used in this syntax match the variable names in your data file.  If you need assistance, contact JRSA.
Download sample SPSS data to be used in this example.  
Download resulting SPSS data created by the syntax.  

The third example looks at the time of day incidents occur on school property.

Example 3.  Incidents on School Property in WV by Hour
Produced by the Division of Criminal Justice Services, Criminal Justice Statistical Analysis Center, Department of Military Affairs and Public Safety, State of West Virginia, in West Virginia School Violence: 1999 - 2000, 2000.

example_3.jpg (69901 bytes)

To deal with the issue of misreporting, the midnight hour was removed from the graph.   To create the graph, offenses occurring at the location code of school/college were selected.  A simple bar graph of the frequency of the incident hour was then produced.  Labels outlining the school day were added.

View SPSS syntax for Example 3.
Download SPSS syntax for Example 3.
Download SPSS table template.
Note: Please check that the variable names used in this syntax match the variable names in your data file.  If you need assistance, contact JRSA.
Download sample SPSS data to be used in this example.  

The final example looks at the time of day sexual assault incidents occur across four victim age categories.

Example 4.  Temporal Distribution of Sexual Assault Within Victim Age Categories
Produced by Howard N. Snyder, National Center for Juvenile Justice, in Sexual Assault of Young Children as Reported to Law Enforcement: Victim, Incident, and Offender Characteristics.  Published by the Bureau of Justice Statistics, 2000.  NCJ 182990.


example_4b.jpg (53510 bytes)

example_4c.jpg (50717 bytes)

example_4d.jpg (51367 bytes)

To illustrate the different times of victimization for victims of different ages, victims are grouped into age categories.  Sexual assault offenses are selected and bar charts are created.

View SPSS syntax for Example 4.
Download SPSS syntax for Example 4.
Download SPSS table template.  
Note: Please check that the variable names used in this syntax match the variable names in your data file.  If you need assistance, contact JRSA.
Download sample SPSS data to be used in this example.