Is web interviewing a good alternative to telephone interviewing? Findings from the International Tobacco Control (ITC) Netherlands Survey
1 Maastricht University/CAPHRI, PO Box 616, 6200 MD Maastricht, the Netherlands
2 STIVORO for a smoke free future, PO Box 16070, 2500 BB The Hague, the Netherlands
3 University of Waterloo, 200 University Avenue West, Waterloo, Canada
4 Ontario Institute for Cancer Research, 101 College Street, Toronto, Canada
5 University of Amsterdam, PO Box 19268, 1000 GG Amsterdam, the Netherlands
BMC Public Health 2010, 10:351 doi:10.1186/1471-2458-10-351Published: 18 June 2010
Web interviewing is becoming increasingly popular worldwide, because it has several advantages over telephone interviewing such as lower costs and shorter fieldwork periods. However, there are also concerns about data quality of web surveys. The aim of this study was to compare the International Tobacco Control (ITC) Netherlands web and telephone samples on demographic and smoking related variables to assess differences in data quality.
Wave 1 of the ITC Netherlands Survey was completed by 1,668 web respondents and 404 telephone respondents of 18 years and older. The two surveys were conducted in parallel among adults who reported smoking at least monthly and had smoked at least 100 cigarettes over their lifetime.
Both the web and telephone survey had a cooperation rate of 78%. Web respondents with a fixed line telephone were significantly more often married, had a lower educational level, and were older than web respondents without a fixed line telephone. Telephone respondents with internet access were significantly more often married, had a higher educational level, and were younger than telephone respondents without internet. Web respondents were significantly less often married and lower educated than the Dutch population of smokers. Telephone respondents were significantly less often married and higher educated than the Dutch population of smokers. Web respondents used the "don't know" options more often than telephone respondents. Telephone respondents were somewhat more negative about smoking, had less intention to quit smoking, and had more self efficacy for quitting. The known association between educational level and self efficacy was present only in the web survey.
Differences between the web and telephone sample were present, but the differences were small and not consistently favourable for either web or telephone interviewing. Our study findings suggested sometimes a better data quality in the web than in the telephone survey. Therefore, web interviewing can be a good alternative to telephone interviewing.