2005-11-04 On 2005-03-14 new files were added to
one or more datasets. These files included additional setup files as
well as one or more of the following: SAS program, SAS transport, SPSS
portable, and Stata system files. The metadata record was revised
2005-11-04 to reflect these additions.
2006-04-05 ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:
- Performed consistency checks.
- Standardized missing values.
- Created online analysis version with question text.
- Performed recodes and/or calculated derived variables.
- Checked for undocumented or out-of-range codes.
2010-04-26 The entire NCRP series is being re-released in restricted format.