or is it those households that are replaced at every interview period? Moving the appropriate incident data from the lower levels of the nested file to the upper level of the household can complicate obtaining a "true" count of the number of households experiencing a victimization event, since many statistical software packages duplicate information at the upper level of the file structure down to the lower level.

Local law enforcement agencies will be participating on a voluntary basis. NIBRS data collection and aggregation at the agency-level will be far more labor and resource-intensive than the current UCR system. What are the implications for coverage and data accuracy?

Criminal justice data have a short shelf life, because detection of current trends is important for planning and interdiction effectiveness. Can new methods be found to process massive data files and produce information in a time frame that is useful to the criminal justice community? Numerous offenses such as sports tampering are not of great national interest. A subset of the full NIBRS file based on scientific sampling procedures could facilitate many types of analyses.

How easy is it to integrate change into such a data system, as evaluations of NIBRS identify new information needs that it will be required to address? Does the sheer volume of data and reporting agencies make this need any more difficult than for smaller on-going data collections? As data storage technology continues to evolve, it is important to weigh both cost and future compatibility needs, particularly in regards to distributing the data to law enforcement agencies and the public. BJS will continue to monitor these technological changes so that we will be able to utilize such advances in order to enhance our analytic capabilities with these large scale datasets.