Enchancing Response Rates
The European Social Survey (ESS) is a cross-national survey series, covering more than thirty countries and employing rigorous methodologies. The minimum target response rate is set at 70 per cent. Statistics Finland, which collects the ESS data in Finland, achieved the target response rate easily for the first two rounds in 2002 and 2004. In 2006, the achieved response rate was only 64%. For the next round in 2008, Statistics Finland decided to try to minimize nonresponse by using special working groups. The ESS and the Finnish Drinking Habits Survey were selected as test cases. Both surveys are collected with face-to-face interviews which on average take about an hour.
Test cases achieved target
Eight response rate enhancing groups were formed for the two surveys in 2008. The regional groups consisted in total of 44 interviewers who were given extra training. The groups met two to four times to discuss persons in their area who had been selected to the sample but had not been interviewed. In the meetings, the interviewers decided which persons they would try to contact again, who would do the contacting and how.
The target response rate was achieved for both surveys. For the ESS, the cases of 400 persons who had not been interviewed were discussed in the groups and one fifth were later interviewed. The achieved response rate was 71.7%. For the Drinking Habits Survey, it was 73.5%.
When the fifth round of the ESS was collected in 2010, no special measures were taken to reduce nonresponse. Response rate was again lower than the target, under 60 per cent. There was no difference between men and women in nonresponse. Nonresponse was biggest among people aged under 35, among never married persons and in urban municipalities.
An important reason for nonresponse were refusals. Most common reasons why people refused to participate were lack of interest (296 out of contacted 3200 in 2010) and lack of time (258 persons). Another relevant type were non-contacts. This group has been growing since the year 2002.
Special measures require more resources
Looking at different ESS rounds in Finland, it can be seen that response enhancing measures increased response by at least 7-8 per cent. However, the measures adopted cost more than Statistics Finland had assumed. Special measures increase response rates but require sufficient resources. In the 2008 test, the funders of data collection paid part of the costs.
The Statistics Finland test also showed that response enhancing measures are demanding for interviewers. Therefore, it would be best if groups working to enhance response would handle only one survey at a time. On the other hand, interviewers felt carrying out such measures had been enlightening and informative.
Surveys and other links:
» FSD2587 Finnish Drinking Habits Survey 2008
» European Social Survey (ESS)
» Statistics Finland