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Standardizing the Display of IBR Data:
Drug Offense Variables

Frequencies and Rate of Missing Data for Drug Offense Variables

Frequencies at a Glance

Rate of Missing None / Unknown / Other Most Common Entry
Offender Suspected of Using 0% 90.4% Alcohol
Type of Criminal Activity 38.8% 27.3% Possessing/Concealing
Property Description 4.7% 20.2% Other
Suspected Drug Type 6.6% 4.9% Marijuana
Estimated Drug Quantity 7.1% -- --
Type of Drug Measurement 6.6% 14.1% Gram

Frequencies of Drug-Related Variables

The 2000 NIBRS file contains 3,104,541 reported offenses and 3,221,250 property entries from 21 states. 

Offender Suspected of Using

All offense entries should indicate whether the offender is suspected of using alcohol, drugs, or a computer during an offense.  In the frequency table below, we see that all of the reported offenses provide the required information.  The vast majority of reported offenses do not include the use of alcohol, drugs, or computers. 

use_freq.jpg (19141 bytes)

When all three possible entries are combined, alcohol use is reported only slightly more often than drug use.  These numbers are presented below. 

use_freq2.jpg (22615 bytes)


Type of Criminal Activity

Most offense entries require at least one entry describing the type of criminal activity associated with the offense.  When only the offenses that required the criminal activity information are selected, we see that almost 40% of the offenses are missing this information.  Almost 30% of the offenses report no or unknown criminal activity.  This percentage may improve, however, as the gang-related codes are being phased in by states as they make improvements to their records management systems.

act_freq.jpg (45548 bytes)

When all three possible entries are combined in the table below, the most commonly reported known criminal activity is Possessing/Concealing, which makes up 65% of the known activity types. 

act_freq2.jpg (41062 bytes)


Property Description

All property entries should provide a description of the property involved in the incident.  Only about 5% of the property entries do not describe the type of property.  The most commonly reported property falls into the Other category, perhaps indicating that additional categories would be useful.  

desc_freq.jpg (98620 bytes)


Suspected Drug Type

All property entries listing Drugs/Narcotics as the Property Description should list at least one of the types of drugs involved.  This entry is not required, however, if the loss type is listed as 'None'. It is also possible that drugs/narcotics are reported in the property description with additional loss types.  In these cases, no entries are allowed in the drug type and drug measurement data elements.

Only about 7% of the drug type entries do not describe the type of drugs. 

type_freq.jpg (42132 bytes)

When all three of the possible drug type entries are combined, it is clear that marijuana is the most frequently reported drug.  


Estimated Drug Quantity and Type of Drug Measurement

Where drugs are listed, the quantity and type of measurement should be present.   Only 7.1% of property entries listing Drugs/Narcotics as the Property Type are missing a quantity.  The drugs reported in NIBRS are most frequently measured in grams.   In the 2000 file, 6.6% of the property entries involving drugs do not have a measurement type specified. 

type_meas_freq.jpg (31587 bytes)

To examine the quantities of drugs reported in the NIBRS file, you must search by drug type and type of measurement.  Since there are many drug and measurement types to examine, the table is too long to be included here.  If you would like to download this output file, click here