Asking Questions - The Definitive Guide To Questionnaire Design ...

ASKING NONTHREATENING QUESTIONS ABOUT BEHAVIOR 63
specify whether or not purchases while on vacation or other trips
should be included. Similarly, in questions about food and drink
consumption, it is necessary to specify whether out-of-home consumption
is to be included or excluded.
When Did it Happen? The “when” question should specify the
time period by using actual dates instead of terms such as “last
week” or “last month.” If an interview is conducted on June 28 and
the respondents are asked about last month, some will consider the
time period from June 1 to June 28 as the last month, and others
will consider the period from May 28. Typical wordings that can be
used are “In the past two weeks, that is, since June 14 . . .” or “in the
past month (or thirty days) since May 21 . . .” It is generally less precise
to ask “When was the last time you did something?” Even if
respondents could remember accurately, this form gives equal
weight to those who do something often and those who do it rarely.
Analyses and conclusions based on such data are likely to be confusing
and misleading. In addition, the memory task is more difficult
for those who do it rarely, so that their answers are subject to
much greater memory errors.
Limiting the time period means that some (possibly many) respondents
will report none of the specified behavior during the time
period. This will bother researchers who are attempting to maximize
the amount of information they get. However, from a perspective
of total survey quality, it is better to minimize the number
of erroneous or potentially erroneous responses.
Asking Why and When Questions. This chapter is not the place
to discuss “why” questions. It is also difficult to discuss “what” questions
in general terms, since the “what” questions depend on the
purpose of your research. You must have a clear idea of why your
study is being done before you start to write questions. Although a
few researchers are able to keep the aims of their study in mind without
formal procedures, most—especially beginning researchers—
cannot. Before you write any questions it is a good idea to put down