Regardless of the methodology used and of the measures that can be taken to assure the best quality, the population census cannot be a perfect operation and there will always be some errors affecting the quality of the census results in terms of coverage and content. For this reason, the agencies responsible for the census should always conduct an evaluation of the quality of the census and provide an assessment of the census coverage and content errors. This is particularly important considering the huge resources invested in the census and the key role played by the census results for the national statistical systems and as primary source of statistical data for the countries. Measuring the census quality, however, is not an easy task, in particular when non-traditional census methods are adopted, for which established census evaluation techniques like the Post Enumeration Survey cannot be applied. In this paper, some issues concerning census quality evaluation are discussed for each of the most common census methodologies, considering the implications on the different dimensions of quality. Some considerations are also presented on census quality evaluation from an international perspective, and on the role that International Organisations can play in this field.

Paper presented at the Joint UNECE/Eurostat Meeting on Population and Housing Censuses, Geneva, 13-15 May 2008.