Improving the design of the Italian permanent population and housing census: a transition towards a massive use of administrative data

The permanent population and housing census (PPHC) has been designed according to the Italian National Institute of Statistics (Istat) modernization program, which places the integrated system of statistical registers at the core of statistical production. The backbone of the PPHC is the statistical Population Register (RBI), whose main sources are the local population registers of Italian municipalities, while two sample surveys (Areal survey and List survey) are conducted annually to evaluate and correct the coverage errors of RBI and collect the data needed to produce Census outputs. Due to fieldwork quality issues, the theoretical design was partly modified during the first PPHC cycle to include the use of administrative data in the estimation process. Furthermore, in 2020, following the cancellation of the field surveys due to the pandemic, a process integrating available data from the past waves and administrative ‘signs of life’ was set up in order to estimate population counts at municipal level for age, sex and citizenship. This obliged push towards a larger use of administrative data has called for a rethinking of the statistical framework for the quality assessment of the estimation processes of the PPHC and, more generally, of the PPHC design, with survey data used for the quality measurement of a fully register-based population count estimation.