In a methodological experiment, carried out within the framework of the Swiss Household Panel, two data collection strategies are evaluated: Computer Assisted Personal Interviews (CAPI) and Computer Assisted Telephone Interviews (CATI). The study was designed as a split-ballot in combination with a Multitrait-Multimethod design.
In the first stage of the test, an initial sample is split up into two halves. One halve of the respondents is interviewed by telephone, the other halve is visited by an interviewer.
In the second stage, the groups are partially crossed over: Part of those interviewed face-to-face the first time are interviewed by telephone the second time, and vice-versa. In all interviews in both waves, a small selection of questions is repeated within the same interview.
A broad range of criteria for comparison are provided by this combined design: costs, speed, response rates, answer distributions and summary statistics, as in the traditional comparison studies. But also estimates of data quality defined as reliability and validity or random and systematic measurement error, associated with the different modes of data collection. In addition, we plan to look at the interaction effects of the mode of data collection and some characteristics of questions that are known to induce response effects, such as sensitivity to social desirable answering and complexity of questions.
These aspects are hypothesized to have differential effects within different mode of data collections. Both modes of data collection included in this study are computer assisted (CATI and CAPI), which augments its significance for the current survey practice and diminishes the lack of knowledge in the literature.