Page 91 - Design for Six Sigma for Service (Six SIGMA Operational Methods)

72 Chapter Four

the in-person interview should be limited to less than an hour. Ideally, the
telephone survey should take between 10 to 15 minutes, mail-out surveys
should take about 15 minutes, and in-person interviews should take less
than 30 minutes.

4.3 Administering the Survey

Once the survey instrument is designed, pretested, and revised, it is time to
administer the survey. For different survey methods, that is, mail-out,
telephone, and in-person, the way of administering the survey will be
different. In this section, we are going to discuss how to administer the
survey for each of these cases.

4.3.1 Administering a Mail-Out Survey
In a mail-out survey, the questionnaire should be designed in the form of a
booklet in order to ensure a professional appearance. Any resemblance to an
advertisement brochure should be strictly avoided. The professional appearance
of the questionnaire is very important to ensure a satisfactory response rate.
There should be adequate spacing between questions. A good cover letter is
very important to explain the purpose of the survey. The questionnaire should be
designed such that it is very convenient for respondents to mail it back.

There are two ways to present the questionnaires to respondents. Questionnaires
can be personally delivered to respondents. This method is more costly in
terms of time and effort, but it is likely to result in a higher response rate, a
more rapid response, a higher percentage of completed questions in the ques-
tionnaire, and perhaps more valid and accurate responses. The other method
is the direct mailing of questionnaires to respondents; this method will usually
result in a lower response rate. Some remedies for this include follow-up
mailings, or follow-up phone calls. Usually these follow-ups should be done
three to four weeks after the questionnaires are sent by mail. Direct mailing
plus the follow-ups usually will achieve a 50 to 60 percent response rate.
Additional follow-ups may raise the response rate to over 70 percent.

4.3.2 Administering a Telephone Survey

The telephone survey is less complex to implement than the mail-out survey.
The most important aspect of the telephone survey is the selection and training
of telephone interviewers. A good source of possible interviewers is uni-
versity students, especially graduate students. The interviewers usually first
study the questionnaire by themselves. Then they are trained in pretest results,
potential tough issues of the questionnaire, and many general ethical issues.