Age structure and age heaping: solving Ireland’s post-Famine digit preference puzzle

The quality of age reporting in Ireland worsened in the years after the 1845–1852 Great Irish Famine, even as measures of educational attainment improved. We show how Ireland’s age structure partly accounts for this seemingly conflicting pattern. Specifically, we argue that a greater propensity to emigrate typified the youngest segment (23–32-year-olds) used in conventional indices of age heaping. Any quantification of age heaping patterns must therefore be interpreted considering an older underlying population which is inherently more likely to heap. We demonstrate how age heaping indices can adjust for such demographic change by introducing age standardization.