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.
- 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.
interviews usually cost more per interview than other methods. This is
particularly true of in-home interviews, where travel time is a major
- 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
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).
- 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.
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.
- 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 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
- 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.
- One way of
improving response rates to mail surveys is to mail a postcard telling your
participant to watch for a questionnaire in the next week or two.
- Another is to
follow up a questionnaire mailing after a couple of weeks with a card asking
people to return the questionnaire.
- The downside is
that this doubles or triples your mailing cost. If you have purchased a
mailing list from a supplier, you may also have to pay a second (and third)
use fee - you often cannot buy the list once and re-use it.
Another way to increase responses to mail
surveys is to use an
These are interviews in which the
Interviewees enter their own answers directly into a computer. They can be used
at malls, trade shows, offices, and so on. Some researchers set up a Web page
survey for this purpose.
- The virtual
elimination of data entry and editing costs.
- You will get more
accurate answers to sensitive questions. Recent studies of potential blood
donors have shown respondents were more likely to reveal HIV-related risk
factors to a computer screen than to either human interviewers or paper
- Employees are also
more often willing to give more honest answers to a computer than to a
person or paper questionnaire.
- The elimination of
interviewer bias. Different interviewers can ask questions in different
ways, leading to different results. The computer asks the questions the same
way every time.
- Response rates are
usually higher. Computer-aided interviewing is still novel enough that some
people will answer a computer interview when they would not have completed
another kind of interview.
- The Interviewees
must have access to a computer or one must be provided for them.
- As with mail
surveys, computer direct interviews may have serious response rate problems
in populations of lower educational and literacy levels. This method may
grow in importance as computer use increases.
Email surveys are both very economical
and very fast. More people have email than have full Internet access. This makes
email a better choice than a Web page survey for some populations. On the other
hand, email surveys are limited to simple questionnaires, whereas Web page
surveys can include complex logic.
- Speed. An email
questionnaire can gather several thousand responses within a day or two.
- There is
practically no cost involved once the set up has been completed.
- You can attach
pictures and sound files.
- The novelty
element of an email survey often stimulates higher response levels than
ordinary “snail” mail surveys.
- You must possess
(or purchase) a list of email addresses.
- Some people will
respond several times or pass questionnaires along to friends to answer.
- Many programs have
no check to eliminate people responding multiple times to bias the results.
- Many people
dislike unsolicited email even more than unsolicited regular mail. You may
want to send email questionnaires only to people who expect to get email
Many email programs are
limited to plain ASCII text questionnaires and cannot show pictures.
(Web Page) Surveys
Web surveys are rapidly gaining
popularity. They have major speed, cost, and flexibility advantages, but also
significant sampling limitations. These limitations make software selection
especially important and restrict the groups you can study using this technique.
- Web page surveys
are extremely fast. A questionnaire posted on a popular Web site can gather
several thousand responses within a few hours. Many people who will respond
to an email invitation to take a Web survey will do so the first day, and
most will do so within a few days.
- There is
practically no cost involved once the set up has been completed. Large
samples do not cost more than smaller ones (except for any cost to acquire
- You can show
pictures. Some Web survey software can also show video and play sound.
- Web page
questionnaires can use complex question skipping logic, randomizations and
other features not possible with paper questionnaires or most email
surveys. These features can assure better data.
- Web page
questionnaires can use colors, fonts and other formatting options not
possible in most email surveys.
- A significant
number of people will give more honest answers to questions about sensitive
topics, such as drug use or sex, when giving their answers to a computer,
instead of to a person or on paper.
- On average, people
give longer answers to open-ended questions on Web page questionnaires than
they do on other kinds of self-administered surveys.
- Current use of the
Internet is far from universal. Internet surveys do not reflect the
population as a whole. This is true even if a sample of Internet users is
selected to match the general population in terms of age, gender and other
- People can easily
quit in the middle of a questionnaire. They are not as likely to complete a
long questionnaire on the Web as they would be if talking with a good
- If your survey
pops up on a web page, you often have no control over who replies - anyone
from Antartica to Zanzibar, cruising that web page may answer.
- Depending on
your software, there is often no control over people responding multiple
times to bias the results.
Scanning questionnaires is a method of
data collection that can be used with paper questionnaires that have been
administered in face-to-face interviews; mail surveys or surveys completed by an
Interviewer over the telephone.
- Scanning can be
the fastest method of data entry for paper questionnaires.
- Scanning is more
accurate than a person in reading a properly completed questionnaire.
- Scanning is
best-suited to "check the box" type surveys and bar codes. Scanning programs
have various methods to deal with text responses, but all require additional
data entry time.
- Scanning is less
forgiving (accurate) than a person in reading a poorly marked questionnaire.
Requires investment in additional hardware to do the actual scanning.
Summary of Survey
Your choice of survey method will depend
on several factors. These include:
Web page surveys are the fastest methods, followed by telephone
interviewing. Mail surveys are the slowest.
interviews are the most expensive followed by telephone and then
mail. Email and Web page surveys are the least expensive for large
and Email surveys offer significant advantages, but you may not be
able to generalize their results to the population as a whole.
and less-educated people rarely respond to mail surveys.
more likely to answer sensitive questions when interviewed directly
by a computer in one form or another.
A need to
get reactions to video, music, or a picture limits your options.
You can play a video on a Web page, in a computer-direct interview,
or in person. You can play music when using these methods or over a
telephone. You can show pictures in those first methods and in a