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

ASKING NONTHREATENING QUESTIONS ABOUT BEHAVIOR 71
findings from Sudman and Wansink (2002) that are relevant to
this topic are as follows:
1. Ledger diaries (as in Figure 2.4), where events are entered
by category, yield slightly more accurate information and are
easier for the diary keeper to fill out and for the researcher to
process than are journal diaries, where events are entered in
the sequence they occur. The categories are helpful because
different types of events require different details. Also, the
headings act as reminders to record keepers of what is
required.
2. Diaries should be kept relatively short—probably no longer
than ten to twenty pages. Longer diaries with more items
cause underreporting, particularly on items on the center
pages of the diary.
3. Diary studies should ask for reports of several items rather
than a single type of behavior or purchases of a single product.
Otherwise, the record keeper will focus on this behavior
and is likely to change this behavior. A diary study that asks
only for reports of purchases of cereal is likely to lead, at
least in the short run, to increased purchases and consumption
of cereal.
Even though they are costly, diaries should be seriously considered
if you are attempting to obtain accurate, detailed information
about frequent, low-salience behavior.
Use the Right Words
The general principle is simple: use words that everyone in the sample
understands and that have only the meaning you intend. Writing
questions that satisfy this principle is a difficult art that requires
experience and judgment. You must expect to engage in a good deal