Response rate is the single most important indicator
of how much confidence can be placed in the results of a
survey. A low response rate can be devastating to the
reliability of a study.
One of the most powerful tool for increasing response
is to use follow-ups or reminders. Traditionally, between
10 and 60 percent of those sent questionnaires respond
without follow-up reminders. These rates are too low to
yield confident results, so the need to follow up on
nonrespondents is clear.
Researchers can increase the response from follow-up
attempts by including another copy of the questionnaire.
When designing the follow-up procedure, it is important
for the researcher to keep in mind the unique
characteristics of the people in the sample. The most
successful follow-ups have been achieved by phone calls.
Many researchers have examined whether postcard
follow-ups are effective in increasing response. The vast
majority of these studies show that a follow-up postcard
slightly increases response rate, and a meta-analysis
revealed an aggregate gain of 3.5 percent. The postcard
serves as a reminder for subjects who have forgotten to
complete the survey.