“Sorry I forgot your birthday!”: Adjusting apparent school participation for survey timing when age is measured in whole years

When only whole years of age are recorded in survey data, children who experienced a birthday since the beginning of the school year may appear to be of school-age when they are not, or vice-versa. This creates an error in estimates of school participation indicators based on such data. This issue is well-known in education statistics, and several procedures attempting to correct for this error have been proposed. The present study critiques current practice and demonstrates that its limitations continue to confound educational research and high-stakes policy conclusions: speculative explanations have been proposed for what is actually a measurement artefact. An alternative adjustment strategy is proposed that coherently exploits all available information and explicitly indicates the remaining uncertainty. The application of the method is illustrated by a number of empirical case studies using recent household survey data. These examples demonstrate that the method is feasible, accurate, and that taking survey timing into account can significantly alter how these data are interpreted.