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Users' Guide to the National Crime Victimization Survey (NCVS) Generalized Variance Functions Appendices

NCJ Number
Date Published
December 2015
11 pages
This document presents the three appendixes of the "Users' Guide to the National Crime Victimization Survey (NCVS) Generalized Variance Functions," which provides documentation for users of the NCVS who calculate variances of estimates from complex sample designs by using generalized variance functions (GVFs), which are models of the relationships between estimates, their characteristics ( i.e., crime type, year, and subpopulation size), and their variances.
Appendix A, "Calculating the Series Adjustment," pertains to Section 3 of the users guide, which discusses calculation totals, proportions, and rates. It notes that series victimizations occur when an NCVS respondent recalls at least six criminal incidents that are similar, but cannot recall the dates and other details of the individual incidents sufficiently to report them separately. When series victimizations are included, calculations of totals and proportions should be based on an adjusted victimization weight, as defined in the example code provided in this appendix. Appendix B addresses "Generalized Variance Function (GVF) Parameters: 1993-2014." GVF parameters, which vary by year and estimate type, should be used for collection-year estimates that include series victimization. The GVF parameters that have traditionally been used to calculate standard errors for the NCVS are provided in the tables of this appendix. The third appendix, which is entitled "Generalized Variance Function 2-Year Correlations: 1993-2014," provides tables that include the 2-year correlation coefficients for the major NCVS crime types for the period 1993-2014.