Many researchers have studied prenotification letters
to determine if they increase response rate. A
meta-analysis of these studies revealed an aggregate
increase in response rate of 7.7 percent. Prenotification
letters might help to establish the legitimacy of a
survey, thereby contributing to a respondent's trust.
Another possibility is that a prenotification letter
builds expectation and reduces the possibility that a
potential respondent might disregard the survey when it
Pre-letters are seldom used in marketing research
surveys. They are an excellent (but expensive) way to
increase response. The researcher needs to weigh the
additional cost of sending out a pre-letter against the
probability of a lower response rate. When sample sizes
are small, every response really counts and a pre-letter
is highly recommended.
1. Briefly describe why the study is being done
and identify the sponsors. This is impressive and
lends credibility to the study.
2. Explain why the person receiving the pre-letter
was chosen to receive the questionnaire.
3. Justify why the respondent should complete the
questionnaire. The justification must be something
that will benefit the respondent. For most people,
altruism is not sufficient justification. If an
incentive will be included with the questionnaire,
mention the inclusion of a free gift without
specifically telling what it will be.
4. Explain how the results will be used.