Using the NIBRS Interactive Code Builder
The Interactive Code Builder provides an easy means of selecting specific variables, merging segments, subsetting cases, and structuring an analysis file at the chosen unit of analysis. Unlike most datasets, NIBRS requires that these tasks be performed for each specific data analysis. The statistical programming for these tasks can be done manually; however, it is a time consuming process, and the potential for error is high. The Interactive Code Builder was developed to expedite the creation of specifically constructed files for statistical analysis. The goals are to free researchers from the burden manipulating data files and allow them to spend more time on analysis.
Essentially the NIBRS Code Builder is a series of choices that the user makes. The result is an SPSS syntax file. The user copies the syntax file from the Web into an SPSS syntax window and runs it on a desktop computer. An SPSS system file structured according to the user's parameters is save on the user's computer. The file is ready for statistical analysis.
Users need to complete two steps before the Code Builder can be fully utilized. (The Interactive Code Builder can of course be used before this, but no data files will be created.)
Step 1 - Get the Data
NIBRS data are available at no charge from the National Archive of Criminal Justice Data. The dataset contains 13 different ASCII data files, one file for each NIBRS record type, a codebook in Portable Document File format, and SAS and SPSS data definition statement files.
Step 2 - Create SPSS System Files
The ASCII data files that are downloaded from the NACJD website are an effective archival and transmission format. However, proprietary system files execute much more efficiently with statistical software. The Interactive Code Builder assumes that SPSS system files have been created. Users should create SPSS system files using the standard data definition statements downloaded from the NACJD website. Standard naming conventions will simplify working with the data. The Code Builder assumes that system files will be named using the segment level:
Filename |
Level |
|---|---|
lb1.sav |
Batch header segment level (1 of 3) |
lb2.sav |
Batch header segment level (2 of 3) |
lb3.sav |
Batch header segment level (3 of 3) |
l01.sav |
Administrative segment level |
l02.sav |
Offense segment level |
l03.sav |
Property segment level |
l04.sav |
Victim segment level |
l05.sav |
Offender segment level |
l06.sav |
Arrestee segment level |
l07.sav |
Group B arrest report segment level |
lw1.sav |
Window exceptionally cleared segment level |
lw3.sav |
Window recovered property segment level |
lw6.sav |
Window arrestee segment level |
Once the system files are created the ASCII data files should be compressed and kept as backups. Downloading of data is no longer necessary.
After the NIBRS data have been downloaded and made into SPSS system files, it is a simple process to create custom analysis files. The NIBRS Code Builder prompts the user with a series of questions and instructions.
First the user selects all of the variables of interest. The variables appear in a picklist organized by NIBRS segment level.
Next, based on the variables chosen, the possible units of analysis to build the file at are listed. The user picks the desired unit of analysis.
Next, the user selects whether to subset cases. Case-level subsetting is available for state codes and UCR offense codes.
Depending upon the variables, unit of analysis, and subsetting chosen, the user chooses how many related records to read.
Remember that NIBRS allows multiple records of a given type for each crime incident. However, the vast majority of crime incidents involve one offense, one victim, and one offender. Choosing to create a file with up to 10 offenses, 999 victims, and 99 offenders will result in an extremely large file. The file will be mostly missing data. It will be larger than the original dataset. And the user may not have sufficient computing resources to analyze it. Typically no more than three related records is necessary to capture over 85% of the incidents in NIBRS.
The above choices are submitted, and in a couple of seconds an SPSS syntax file is displayed.
This syntax file is the product of the Interactive Code Builder. It is a file that can be used to create an SPSS system file built to the user supplied specifications. This file should be copied into an SPSS syntax window and run. An SPSS system file will be saved onto the user's PC.
Use the Interactive Code Builder
