Fine Differences - Anticipating the Effects of Switching from Off-Iine to Online. The presentation gives an overview of methodological studies dealing with dif­ferences in awareness, image and preference measurements between Off-line and On-line gathered data. Existing differences between both approaches can be caused by either sample or method effects.

Sample effects can be traced back to different sample characteristics (e.g. distinct affinity to technology or media usage behaviour between On-liner and Off-Iiner), whereas method effects depend on distinctive features of the data collection set­ting (e.g. whether an interviewer is attendant or not).

Published and own side-by-side studies will be outlined and summarised to iIIumi­nate the importance and specificity of both effects.

The presented results show systematic differences in relevant variables between personal, telephone, and web-based interviews. Among others, aided advertising awareness figures generally show the following relationship: CAPI < Online >= CATI. Furthermore, effects for image and preference measurements are exami­ned. Hypotheses for systematic differences, but also the reasons for observed exceptions will be discussed.

The results of the presentation help marketing researchers to assess which ef­fects can be expected when migrating from Off-line to On-line.