Standardizing the Display of IBR Data: Injury Variables

Frequencies and Rate of Missing Data for Injury Variables

Frequencies at a Glance

Rate of Missing? 1% for required offenses
Most Common Injury? Apparent Minor Injury
Number of Injuries Reported? Usually only 1 reported

Frequencies of Reported Injuries

The 1999 NIBRS file contains 2,311,625 victims from 18 states; 1,587,277 of these are individuals.  All of the possible injury types occur in the file.  Of all reported individual victims (excluding businesses and society), 238,976 (15%) experienced at least one injury. 

Despite there being a category for "None", 69% of the victims are missing an entry for injury type.  These most likely represent offenses that do not require injury information and can be checked by looking at only the offenses requiring victim information. 

Of the reported injuries, apparent minor injuries are the most commonly reported, at 90%.  The frequencies for each injury type (for the first injury variable only) are presented below.


Frequencies of Reported Injuries for Required Offenses

When only the offenses that require an injury entry (kidnapping/abduction, forcible rape, forcible sodomy, sexual assault with an object, forcible fondling, robbery, aggravated assault, simple assault, and extortion/blackmail) are selected, we see that there are still some missing injuries; all are for robbery offenses.   Since there can be multiple offenses entered, each of the possible offense columns should be checked.  The first three offense code entries are displayed below.

 injury_offense1.jpg (97780 bytes)

injury_offense2.jpg (89413 bytes) injury_offense3.jpg (60859 bytes)

Number of Reported Injuries per Offense

Part of the advantage of NIBRS is the ability to capture a wealth of information; it is possible to report up to five injuries per victim in NIBRS.  The table below presents the number of injuries for victims who reported at least one injury.  

As the table shows, either very few offenses involve multiple injuries or these injuries are not being reported.  Only 1.5% (3,640) of all victims with injuries reported at least two; only 23 of the victims with injuries reported at least 5 injuries (.01%).

 num_injuries.jpg (21466 bytes)