Measuring the Quality of the Finnish Population Register with a Survey Special focus on non-response Päivi Hokka and Markku Nieminen Statistics Finland Survey Research Unit

10th July 20082Päivi Hokka Q2008 Structure of the presentation Aims and design of the Finnish Population Register Quality Study Methods of investigating non-response Results of the non-response analysis of 2007

10th July 20083Päivi Hokka Q2008 The Population Register Contains basic information about Finnish and foreign citizens living permanently in Finland Information is based on notifications made by private individuals and public authorities Considered as a high-quality register also at the international level

10th July 20084Päivi Hokka Q2008 Quality Study Register quality is examined with the help of a survey Idea: to ask people directly, whether the register information on them is correct or not Conducted by Statistics Finland annually since 1998 Telephone interviews made by statistical interviewers The questions are added to the end of Statistics Finland's Labour Force Study Sample size 11,000 (persons aged )

10th July 20085Päivi Hokka Q2008 Variables checked in the Quality Study Permanent address Type of ownership of permanent home Native language Occupation A citizen’s permanent address is the most important The interviewer reads out the address the respondent has according the Population Register and asks, whether it was the address of his/her permanent home

10th July 20086Päivi Hokka Q2008 Answers to the question concerning permanent address in Quality Study 2007 Non-response = 1,205

10th July 20087Päivi Hokka Q2008 Non-response as a challenge Response rate about 88 – 90 per cent Sample of 11,000 ——> over 1,000 non-response cases Threat for the credibility of the Quality Study Since 2003, the validity of the permanent address variable has been intensively inquired for all non-response cases

10th July 2008Päivi Hokka Q2008 The non-response 1)People who can be contacted successfully, but who do not answer the questions - most of them refuse 2) People who cannot be contacted at all

10th July 20089Päivi Hokka Q2008 Tactics in investigating non-response The respondent or a substitute contacted A short question about the permanent address

10th July Päivi Hokka Q2008 Tactics in investigating non-response The respondent or a substitute contacted No contact A short question about the permanent address Comparison with 1) postal address register 2) Fonecta Finder Visit in the address

10th July 2008Päivi Hokka Q2008 Correctness of addresses of non-response cases in 2007

10th July Päivi Hokka Q2008 Correct addresses among non-response (N=1,096) 27% checked from the respondent or a substitute 23% checked with a visit 42% compared with the postal address register 7% compared with Fonecta Finder

10th July Päivi Hokka Q2008 Result of the Quality Study 2007 with and without non-response * When non-response is included, the number of checked cases is 10,753. Missing are the 54 unchecked cases.

10th July 2008Päivi Hokka Q2008 Correct address %

10th July 2008Päivi Hokka Q2008 Conclusions By investigating the non-response cases, as many as 99.5 per cent of the permanent addresses of the sample could be checked The quality of register information was found to be worse among the non-response cases than the respondents The reservations in the Quality Study method are linked to the accuracy of the other databases used in comparisons Intensified inquiries of non-response cases help in approaching the ”truth”