A question like the following often appears on
questionnaires sent to samples of college students:
Age :
1) below 18
2) 18-19
3) 20-21
4) over 21
If there is a specific need to generalize results to older or younger
students, the question is valid. Also, such a question might be included to
check on the representativeness of the sample.
However, questions like this
are often included in an apparently compulsive effort to characterize the
sample exhaustive.
A clear-cut need for every question should be
established.
This is especially important with respect to questions
characterizing the responders, because there may be a tendency to add these
almost without thought after establishment of the more fundamental
questions.
The fact that such additions may lengthen the questionnaire
needlessly and appear to pry almost frivolously into personal matters is
often overlooked.
Some questionnaires ask for more personal data than
opinions on their basic topics.
In many cases, personal data are available from sources other than the
responders themselves.
For example, computer files used to produce mailing
labels often have other information about the subjects that can be merged
with their responses if these are not anonymous. In such cases, asking the
responders to repeat this information is not only burdensome but may
introduce error, especially when reporting the truth has a negative
connotation. (Students often report inflated grade-point averages on
questionnaires.)
