The Role of the NCES Disclosure Review Board in Balancing Confidentiality and Data Quality

• Activity Number: 69
• Type: Topic Contributed
• Date/Time: Sunday, July 29, 2012 : 4:00 PM to 5:50 PM
• Sponsor: Section on Government Statistics
• Author(s): Marilyn Seastrom*+
• Companies: National Center for Education Statistics
• Keywords: disclosure avoidance ; data swapping ; Hellinger Distance ; data quality

Abstract

Matching with publicly available data bases was the first component of disclosure avoidance in NCES public-use data files. Typically matches are avoided by recoding variables, but at times perturbations are required. In 2002, the NCES DRB added the use of data swapping in NCES restricted-use and public-use data files as an additional means of disclosure avoidance. To facilitate this change, NCES supported the development of "Dataswap" software. Pre-swapped and swapped data were compared using different levels of swapping to examine the impact of swapping on data-quality. In 2010, a measure of the Hellinger Distance was added to the Dataswap software. This measure is compared across different swapping alternatives to identify an acceptable alternative that does the least "harm" to the distribution of the data, thus enhancing data quality. The most recent innovation involves the inclusion of a routine in Dataswap that identifies the variables and cases that are most at risk of disclosure, thus allowing for a more precise targeting of the data to be swapped. This is used to increase the level of data protection, while targeting the swapping where it is most effective.