This paper is intended to inform interested parties of ongoing research and to encourage discussion of work in progress. The views expressed on methodological, technical and operational issues are those of the authors and not necessarily those of the U.S. Census Bureau. Some of the data used in this paper are confidential. All results have been formally reviewed to ensure that no confidential Census Bureau data have been disclosed. The U.S. Census Bureau supports external researchers’ use of some of these data through the Research Data Center network (www.census.gov/ces).

Earnings instability is measured to have different levels depending on the data source and type of measure. Understanding trends in earnings instability is important to understanding inequality, and if instability results based on survey data are inaccurate, administrative data may be a valuable alternate resource. We explore this topic by measuring earnings instability for the same set of individuals using multiple data sources: the Survey of Income and Program Participation (SIPP) and administrative earnings records from the Social Security Administration. We compare instability results for years ranging from 1984 to 2010 from the two data sources and also investigate how instability estimates are sensitive to different measures. Our results show a marked difference in instability estimates for the two data sources. In almost all cases, instability results based on the SIPP are higher than those based on the administrative data. Additionally, trends in instability differ depending on the data used.