The main purpose of this paper is to measure the accuracy of age-sex data collected in the 2011
Population and Housing Census (PHC) at the national level. Demographic analysis tools are employed
to evaluate the 2011 PHC data, this is in cognizance of the fact that the vital registration system is
incomplete and there was no post-enumeration survey conducted. On the basis of Whipple’s Index,
Myers indices and Bachi index, the quality of age reporting in the Botswana’s 2011 census data is very
good, and the data show that there was no serious digit preference. However, the results from the UN
Age-Sex Accuracy Index indicate that the 2011 population census age data are not of good quality, with
an index score of 21.0. It should be noted that the UN Age-Sex Accuracy Index is unable to separate
the inaccuracies and natural changes which raise questions of reliability of the index. The application
of the P/F ratio method in the evaluation of 2011 census data shows that ratios are above unity. This
pattern implies that there is either an error of underreporting of current fertility relative to lifetime
fertility or suggests a declining fertility trend in Botswana in the recent past or the mean parities were
over-reported. The fi rst two scenarios are more probable while the last one is highly unlikely given
existing evidence. Overall it can be concluded that the census data is of acceptable quality and therefore
the 2011 population data could be used to derive credible estimates.