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User's Guide to National Crime Victimization Survey (NCVS) Direct Variance Estimation: Appendix F - Examples in STATA

NCJ Number
Bonnie Shook-Sa; G. Lance Couzens; Marcus Berzofsky
Date Published
December 2015
49 pages
This "Appendix F" of the "User's Guide to National Crime Victimization Survey (NCVS) Direct Variance Estimation" provides examples of the use of STATA, a general purpose statistical software package created in 1986 by StataCorp, with NCVS statistics.
In STATA, the NCVS sample design must be appropriately specified by using the "svyset" command each time a new data set is used for analysis. This command is provided in this appendix. The nested stratification requires creation of a stratum recode prior to "svyset." Examples are presented as if they were run in sequences; therefore, data sets are cleared and set to use, and the "svyset" command is included only when necessary and not for each example. For the calculation of victimization rates, analysts must first create a new variable equal to the product of the victimization count and the adjustment factor (ADJINC_WT), multiplied by 1,000. The "subpop" option is used to limit the analysis to the appropriate set of cases. Prior to each analysis, a "sub" variable is created based on all exclusions. Examples 1 and 2 demonstrate how to estimate the total number of victimizations. Examples 3 and 4 show how to calculate the proportion of victimizations with given characteristics. Examples 5 and 6 demonstrate the calculation of personal and property victimization rates for victimization characteristics included on the modified person and household files. Example 7 indicates the calculation of victimization rates for victimization characteristics not on the modified files. Examples are included for both single- and pooled-year estimates. Example 8 demonstrates how to identify low-quality estimates and implement the rounding recommended and discussed in "section 4" of the user's guide.