This chapter examines data quality issues for the analysis of consumption inequality, exploiting two complementary data sets from the Consumer Expenditure Survey—one known as the Interview sample and the other as the Diary sample. It develops a methodology that extracts and combines the most reliable information from each sample to derive a correction for the measurement error affecting observed measures of consumption inequality in the two surveys. It concludes that consumption inequality, as measured by the standard deviation of the log of nondurable consumption, has increased by roughly 5 percent during the 1990s.