The paper focuses on the two main activities which took place in 2007 and 2008 at the Statistical Office of the Republic of Slovenia in order to improve the census count in the register based Census of Population and Housing in Slovenia in 2011. The first activity was focused on the identification of potential so-called ˝administrative survivors˝ in the Central Population Register (hereinafter CPR) among population aged 80 years or over. The second activity was the introduction of the census usual residence concept in the quarterly population statistics.

Due to the ageing of populations in the developed countries and the increase in the number of the persons aged 80 or over there is a tendency among national statistical institutes to disseminate also the population by the oldest age-groups (90 or more, 100 or more) and even more, to cross-tabulate these age groups with socio-economic topics. It is well known that the uncertainty and unreliability of the population estimates and population counts are higher for the oldest age-groups. Therefore at Slovene national statistical institute the analysis of potential ˝administrative survivors˝ in the age group 80 or over was done in order to improve the quality of the census count at the 2011 register-based census. On the basis of several analyses estimations were made that the centenarians in the quarterly population statistics are overestimated by about 15-20 per cent and the nonagenarians by about 2-3 per cent.

Paper presented at the joint UNECE/Eurostat meeting on Population and Housing Censuses, Geneva, 28-30 October 2009.