2013 Post Enumeration Survey

Respondents in the PES are individually matched to census forms by comparing the information given by PES respondents with the information given on census forms. Measures of undercount and overcount are estimated from the results obtained in the matching procedure. Two major changes from the 2006 PES are the increased sample size (15,000 dwellings compared to 11,000) and the introduction of automatic matching of records to supplement clerical matching between PES and census. The net undercount estimates produced from the PES are subject to both sampling and non-sampling errors. The enhanced sample size aimed to reduce the sampling error of coverage estimates, especially for population sub-groups, and the introduction of automatic matching significantly improved the quality of the estimated coverage. Reduced non-sampling error was also expected due to improvements in the quality of the matching, enumeration and interviewing practices compared with 2006. Matching was done to determine if a PES respondent was counted in the census at the address at which they were interviewed in the PES or at each address where a census form may have been completed for them (this is referred to as the "search address"). This was achieved by comparing the information given by PES respondents with the information given on census forms. If an address given was different to the PES address, searching was carried out to locate the address. The estimation methodology for the 2013 PES includes several improvements over that used in 2006, 2001 and 1996. The main change was to include a dwelling weighting step to adjust for dwelling-level non-response in the PES. This enables us to take into account the extra information we have about census attributes of dwellings found in the census. A matching impact study (MIS) was undertaken on a subsample of PES records. This study evaluated the new method of automated electronic matching against the manual-only method used previously, in order to measure the effect of the change in method. The MIS verified that the 2013 PES results improved the quality of matching. The overall impact is a reduction in the net census undercount from the new method because we were able to locate more people who gave vague or inaccurate census-night addresses in the PES. In the MIS, the national net undercount rate was estimated to be 3.9 percent (+/- 0.6 percent), compared with 2.4 percent (+/- 0.5 percent) using the new method. en-NZ