Age heaping among adults in Nigeria

Age, as a variable, represents a critical basis for demographic classification; thus, its misrepresentations or
misreporting alter the accuracy of demographic estimates. This paper examines the extent and pattern of
age heaping in the age data for adults, collected in the Nigerian Demographic Health Survey (NDHS). The
study used the NDHS data for 2003, 2008, and 2013 to compute a Whipple’s and Meyers’ blended index for
each survey year, by gender, geopolitical zones, states and place of residence. The analysis shows that age
heaping was higher than the acceptable levels in all three data sets. The Whipple’s index puts the rate of age
heaping in the 2003 dataset at 271.3, whilst the rates declined slightly in the 2008 and 2013 datasets to reach
204.2 and 202.5 respectively. Similarly, the Myers’ blended index portrayed that age heaping in the 2003
data was highest at 47.0 while the subsequent years were lower at 38.60 and 38.66, respectively. Digits
ending in 0 and 5 were mostly reported in all three surveys and higher rates of age heaping were observed
among males, the uneducated and rural dwellers. Age heaping was prominent in all three surveys, thus
affecting the data quality gathered at these surveys. Thus, future studies should assess the extent to which
age misreporting could bias the estimate of fertility rate.