| Once
you have decided on your sample you must decide on your method
of data collection. Each method has advantages and disadvantages.
Personal Interviews
An interview is called personal when the
Interviewer asks the questions face-to-face with the Interviewee.
Personal interviews can take place in the home, at a shopping
mall, on the street, outside a movie theater or polling place,
and so on.
Advantages
* The ability to let the Interviewee see,
feel and/or taste a product.
* The ability to find the target population. For example,
you can find people who have seen a film much more easily
outside a theater in which it is playing than by calling phone
numbers at random.
* Longer interviews are sometimes tolerated. Particularly
with in-home interviews that have been arranged in advance.
People may be willing to talk longer face-to-face than to
someone on the phone.
Disadvantages
* Personal interviews usually cost more per
interview than other methods. This is particularly true of
in-home interviews, where travel time is a major factor.
* Each mall has its own characteristics. It draws its clientele
from a specific geographic area surrounding it, and its shop
profile also influences the type of client. These characteristics
may differ from the target population and create a non-representative
sample.
Telephone Surveys
Surveying by telephone is the most popular
interviewing method in the USA. This is made possible by nearly
universal coverage (96% of homes have a telephone).
Advantages
* People can usually be contacted faster
over the telephone than with other methods. If the Interviewers
are using CATI (computer-assisted telephone interviewing),
the results can be available minutes after completing the
last interview.
* You can dial random telephone numbers when you do not have
the actual telephone numbers of potential respondents.
* CATI software, such as The Survey System, makes complex
questionnaires practical by offering many logic options. It
can automatically skip questions, perform calculations and
modify questions based on the answers to earlier questions.
It can check the logical consistency of answers and can present
questions or answers choices in a random order (the last two
are sometimes important for reasons described later).
* Skilled interviewers can often elicit longer or more complete
answers than people will give on their own to mail, email
surveys (though some people will give longer answers to Web
page surveys). Interviewers can also ask for clarification
of unclear responses.
* Some software, such as The Survey System, can combine survey
answers with pre-existing information you have about the people
being interviewed.
Disadvantages
* Many telemarketers have given legitimate
research a bad name by claiming to be doing research when
they start a sales call. Consequently, many people are reluctant
to answer phone interviews and use their answering machines
to screen calls. Since over half of the homes in the USA have
answering machines, this problem is getting worse.
* The growing number of working women often means that no
one is home during the day. This limits calling time to a
"window" of about 6-9 p.m. (when you can be sure
to interrupt dinner or a favorite TV program).
* You cannot show or sample products by phone.
Mail Surveys
Advantages
* Mail surveys are among the least expensive.
* This is the only kind of survey you can do if you have the
names and addresses of the target population, but not their
telephone numbers.
* The questionnaire can include pictures - something that
is not possible over the phone.
* Mail surveys allow the respondent to answer at their leisure,
rather than at the often inconvenient moment they are contacted
for a phone or personal interview. For this reason, they are
not considered as intrusive as other kinds of interviews.
Disadvantages
* Time! Mail surveys take longer than other
kinds. You will need to wait several weeks after mailing out
questionnaires before you can be sure that you have gotten
most of the responses.
* In populations of lower educational and literacy levels,
response rates to mail surveys are often too small to be useful.
This, in effect, eliminates many immigrant populations that
form substantial markets in many areas. Even in well-educated
populations, response rates vary from as low as 3% up to 90%.
As a rule of thumb, the best response levels are achieved
from highly-educated people and people with a particular interest
in the subject (which, depending on your target population,
could lead to a biased sample).
How
to design a questionnaire |
Steps
in building a questionnaire |
A
good Questionnaire |
Interviewing
Methods |
Questionnaire
Design
| Ten
Tips to design a Questionnaire
|
