One of the main difficulties encountered by users of statistical information is the possibility of comparing data in a long time series. Bearing this constraint in mind, the main goal of this study is to harmonise the concepts of present population and resident population with the population figures for the two categories, beginning with the first population census. We further intend to evaluate the quality of the census data by using a number of techniques to
correct age and gender breakdown.

keywords: census, resident population, present population, age, quality indices of the censuses results.