Telephone interviewing marks its beginning in the 1980s. It may be regarded as a semi-personal method of information collection. It has become much more popular in recent years because of the diffusion of telephone services worldwide.
The increase in the use of telephone interviewing in the last few years has been so dramatic that it has prompted full applications in survey research during the past few years.
The chief reason, as we pointed out, is the rapid increase in the number of households having telephones and the widespread use of computer-aided technologies all over the world, which enables us to avoid some of the damaging sampling problems that previously plagued telephone survey.
Many people are hesitant to admit strangers, especially at night, for face to face interviews.
The same is the case with the interviewer, who also remains hesitant to approach a strange neighbor.
All these factors plus others have helped the telephone survey to make inroads on the dominance of the face-to-face interview and mailed questionnaire.
Advantages of Telephone Interviewing
Of the advantages that telephone interviewing offers, the following are frequently cited:
- It is quicker than the mail survey;
- It is less expensive than interviewing. Groves and Kahn (1979, p: 223, see Cooper p: 300) report that sampling and data collection costs for telephone surveys can run from 45% to 64% lower than comparable personal interviews;
- The respondents remain more anonymous than in a personal interview;
- The interviewer can prompt the respondents to answer difficult questions whenever necessary. This is not possible in mail survey;
- The sample needs not to be geographically contiguous, but can be dispersed throughout the study;
- The method is particularly rewarding for studies among telephone subscribers and organizations.
Disadvantages of Telephone Interviewing
The disadvantages are as follows:
- The respondents are often less motivated over the telephone;
- The respondents can terminate the interview at any stage of the interview if he is reluctant to continue for any reason;
- Visual materials cannot be shown if needed;
- The interviewer is unable to observe the respondent and thus cannot gather nonverbal data;
- The interviewer cannot persuade the respondent to complete the interview and standardize the environment in which the interview takes place;
- The method is unsuitable in areas where people have inadequate telephone subscription facilities;
- In some societies, it is costly too.
How to Conduct a Telephone Interview?
With the advent of modem computer technologies, telephone interviewing processes have become easier than before. One of such methods is the Random Digit Dialing (RDD), which enables us to avoid some of the sampling problems that we encountered before in telephone interview.
One chief reason for this was that the sampling frame could be used because many telephone numbers were not listed in the directory.
Also, some numbers were listed more than once, giving them an increased probability of selection of the sample. RDD is a process for mechanically dialing randomly, from all possible combinations of the digits in a set of working telephone numbers.
The RDD can reach all working numbers with equal probability. Since the researcher does not have to work with directories, there is also no biasing problem.
Despite its several appealing advantages, it suffers from the bias arising out of the situation when a household possesses more than one telephone.