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

ASKING QUESTIONS FAQS 331
guish between married versus single households, it would be better
to have only two response categories, “Married and living with
spouse” and “Other.”
It is also a good idea to avoid scale-point proliferation—for
example, (1) Never, (2) Rarely, (3) Occasionally, (4) Fairly often,
(5) Often, (6) Very often, (7) Almost always, (8) Always. These
types of answers can annoy or confuse the respondent because of
the hairsplitting they entail. In contrast to category proliferation,
which seems usually to arise somewhat naturally, scale-point proliferation
takes some thought and effort.
Although sensory research traditionally uses 9-point scales,
psychometric research has shown that most subjects cannot reliably
distinguish among more than six or seven levels of response.
For attitude-related work, four to five scale points may be quite sufficient
to stimulate a reasonably reliable indication of response
direction.
What About Open-Ended Questions?
One potentially valuable part of any survey questionnaire consists
of the open-ended questions. These are questions that don’t restrict
answers to prescribed categories. (See Chapter Five.) 1
When evaluating service satisfaction, for instance, open-ended
questions can point to the service issues that are most important to
customers. Although customers might rate a number of service
aspects as low or high, it will be the vehement comments or the
effusive ones that will show what is really important to them.
Often valuable information from open-ended questions is
wasted because researchers pay attention only to the most commonly
mentioned open-ended answers and not to the unique ones.
Open-ended questions can uncover uncommon but intelligent
opinions, but if surveyors focus only on frequent responses, they will
continue to be unaware of these ideas. 2 (See Appendix D for an
example of a brief open-ended survey.)