This document identifies the several reasons why a topic that is being considered for inclusion in a traditional census of population and housing may be regarded as ’difficult-to-measure’. The document comments on the reasons why this may be so for a number of those topics which have been recommended for inclusion in a Census by the Conference of European Statisticians and some others that are not included in the Recommendations. The document notes those topics which are unlikely to be included in the 2011 UK Census for one or more of these reasons. The document also recognises that, though difficult to measure, some topics are, nevertheless, being proposed for inclusion. It concludes by suggesting those topics that might be considered the most difficult to measure.

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

[Paper also available in French and Russian]