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Sub-national Estimates in the NCVS

Learn about utilizing sub-national estimates in the NCVS for stakeholders at national and state levels. Explore strategies, direct and indirect estimates, boosts, and generic area estimations. Provide feedback on data precision and utility.

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Sub-national Estimates in the NCVS

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  1. Sub-national Estimates in the NCVS Bureau of Justice Statistics June 7, 2012

  2. Utility of Sub-national Estimates • Crime is always local and sometimes national. • NCVS is designed to provide national estimates. • National estimates are useful for many purposes. • Sub-national estimates can be useful both for stakeholders at the national level as well as states and large cities.

  3. BJS’ Approach to the Issue • Identify estimates that can be made with the NCVS data and are of sufficient precision. • Determine if these estimates are useful or how they can be made useful to stakeholders. • This webinar is one of a number of meetings where we can present preliminary products and work with stakeholders to determine their utility.

  4. Outline of the Presentation • Present general outline of strategies for producing sub-national estimates. • Present various products using these various strategies and get your reaction. • Can the product be understood? • Can you find yourself in these data? • Is the information useful? • When would you use it? • Are all important distinctions made?

  5. Range of Strategies

  6. Definitions • Direct estimates are made exclusively with actual samples from the NCVS. • Indirect estimates are modeled estimates using correlates of victimization with existing NCVS sample, if available, in the jurisdiction. • Sample boosts refer to increases in sample size. • Reallocation refers to redistributing the sample so that it is more suitable for sub-national rather than national estimates. • Accumulation (rolling averages) is the combining of annual samples for greater precision, e.g. 3-years, 5-years.

  7. Generic Area Estimates • Sometimes it is sufficient to have an estimate from areas “like” yours. • Estimates for areas “like” yours are formed by taking all of the NCVS interviews conducted in areas like yours. • Areas “like” yours are formed by identifying a number of attributes and defining as similar those areas that have similar values on these attributes. • We have illustrations with the public use files but other area identifiers are available in Census data.

  8. Generic Areas • Create a typology of “like places” using available data • Region: Northeast, Midwest, South, West • Population size: • Not in a place • Under 10,000 • 10,000-49,999 • 50,000-99,999 • 100,000-249,999 • 250,000-499,999 • 500,000-999,999 • 1,000,000 or more • MSA status: Rural, Suburban, Urban • Typology based on combination: MSA X Region X Population size • Example: “city with a population of 250,000-500,000 in the Northeast” represents places such as Buffalo, NY, and Pittsburgh, PA.

  9. Direct Estimates • NCVS has enough sample in some states to produce estimates of reasonable precision for violent crime. • Rolling up three years will allow us to make more precise estimates for big states and reasonable estimates for more states. • Estimates for prevalent classes of property crime are easier. • Sample boost and re-allocate allow more states to be included.

  10. Boosts • Boosts determined by the desired precision of the total violent crime estimate for the specified number of states. • Relationship between boosts and states done in this manner because of the need to treat states as strata in sample reallocation. • State strata for all states with population over 8M (12). • CA,TX,NY,FL, IL, PA, OH,MI,GA,NC,NJ,VA • State strata for all states with population over 6M (17). • CA,TX,NY,FL, IL, PA,OH,MI,GA,NC,NJ,VA • WA,MA,IN,AZ,TN • State strata for all states with population over 5m (22). • CA,TX,NY,FL, IL, PA, OH,MI,GA,NC,NJ,VA • WA,MA,IN,AZ,TN • MO, MD,WI,MN,CO

  11. California: 3-year rolling averages for violence, by type of crime

  12. California: NCVS and UCR Violent Crime Rates

  13. California: NCVS and UCR Violent Crime Counts

  14. 40 Largest Metropolitan Statistical Areas (MSAs) in NCVS

  15. Indirect Estimates • Methods that use NCVS data in combination with other data to make estimates for states and large cities. • Primary method for making estimates for the 28 smallest states as well as smaller cities without sufficient sample for direct estimates. • We are assessing various models using NCVS and UCR data over time.

  16. Summary • For many years the NCVS ignored the issue of sub-national estimates. • In the last three years we have done some serious research and development work that has resulted in a multi-faceted approach to producing sub-national estimates. • The future and future directions of this program will depend on the response of stakeholder groups like you. • We need your feedback on how these estimates could contribute to your ability to do your job and to serve the clients that you serve. • Hopefully this session is the beginning of a dialogue on these issues.

  17. Contact Information Michael Planty, Victimization Statistics Michael.Planty@usdoj.gov

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