This paper examines the properties and prevalence of measurement
error in longitudinal earnings data. The analysis compares Current
Population Survey data to administrative Social Security payroll tax
records for a sample of heads of households over two years. In contrast
to the typically assumed properties of measurement error, the results
indicate that errors are serially correlated over two years and
negatively correlated with true earnings (i.e., mean reverting).
Moreover, reported earnings are more reliable for females than males.
Overall, the ratio of the variance of the signal to the total variance is
.82 for men and .92 for women. These ratios fall to .65 and .81 when the
data are specified in first-differences. The estimates suggest that
longitudinal earnings data may be more reliable than previously believed.