Abstract

It is widely accepted that mixing data collection modes is an effective way to reduce survey nonresponse. This is because different data collection methods may engage different respondent groups, thus improving coverage, reducing the rate of nonresponse errors, and making data collection more cost-effective. However, mode effects may also occur.
Due to declining response rates (RRs), the Hungarian Central Statistical Office conducted the Population Monitor Survey, incorporating a field experiment where a probability sample selected from the Hungarian registry of addresses was randomly divided into three groups with different sequential mix-mode data collection protocols. In the first group (A), the sample elements were initially contacted by telephone (CATI) after not responding the survey online (CAWI). If the telephone contact resulted in nonresponse, an interviewer visited them in person (CAPI) at their registered or temporary address. In the second group (B), after the online option, an interviewer visited the nonrespondents in person at their address, and after two weeks, the unsuccessful cases were transferred to CATI. The third group (C) contained sample elements for whom no telephone number was available from the mobile service providers. In consequence, after the online response option, an interviewer contacted them directly, and CATI response was not available for them. To nonrespondents from all groups a final notification letter was sent out to re-invited for a final CAWI phase.
The aim was to reveal how the order of data collection modes may affect the RR, respondents’ characteristics and response quality. Additionally, it was also examined to what extent nonrespondents can be converted by reintroducing a post-fieldwork CAWI option.
International empirical research shows that the data quality from CAPI questionnaires can be better than that obtained from CATI questionnaires, and the refusal rate is significantly lower with the CAPI data collection method. During the Population Monitor Survey, the completion time, response rate to questions about personal data, and income accuracy were of better quality in online and telephone data collection than in personal interviews, although in all groups, the response rate was highest in the CAPI mode still.
When reversing the data collection modes, it was found that a 71.6% completion rate was observed in the CAPI-CATI sequence (B) and a 69.6% completion rate was observed in the CATI-CAPI sequence (A), but no significant difference was found between the two groups.
Different sequences led to notable differences in settlement type and income. Other results were generally not significant. In the final phase, when CAWI was reintroduced, 25% of all previous nonrespondents were successfully converted, contributing greatly to achieving a high overall response rate (RR) of 72.37%, demonstrating that carefully planned data collection designs can attain seemingly unattainable response rates. Group-specific results of the experiment will also be presented and discussed at the conference.