Design of follow-up questions in Web surveys

We describe a qualitative study on how to design follow-up questions in self-administered computer-based surveys. Three different designs were examined: follow-up question on the next page, initially invisible on the same page, and initially greyed-out on the same page. The last design was definitely the worst and cannot be recommended. There are some indications that the second design might be preferable, at least when other design elements (such as graphics) do not make the page difficult to render.