SURVEY METHODS

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.
• 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.

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.
• 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

Computer Direct Interviews

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.

Advantages

• 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 questionnaires.
• 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.

Disadvantages

• 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

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.

Advantages

• 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.

Disadvantages

• 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 from you.

Many email programs are limited to plain ASCII text questionnaires and cannot show pictures.

Internet/Intranet (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.

Advantages

• 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 the sample).
• 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.

Disadvantages

• 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 demographics.
• 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 interviewer.
• 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

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.

Advantages

• 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.

Disadvantages

• 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 Methods

Your choice of survey method will depend on several factors. These include: