A careful evaluation of the following seven factors serves as the criteria for selection of a survey technique:
Criteria # 1. Cost:
The cost of conducting a personal interview are higher as compared to telephone and mail surveys. The interview are higher personal interviews are due to high transportation expenses of the interviewer and time devoted on each of the interviews.
These costs increase because the interviewer has to move door-to-door for contacting the respondents. From the cost point of view, the mail survey is hedged as the best. The telephone survey involves more costs than mail survey.
Criteria # 2. Speed:
Considering the time period devoted by the investigators in getting the responses, it is observed that the personal interviews consume maximum time. Also in the case of mail survey, the investigator has to fair for a longer time period for getting the response. But the speed of getting response is the highest in a case of telephone survey which can be conducted within a limited period of time from a single control room. Thus, speed-wise telephone survey is the best survey techniques.
Criteria # 3. Accuracy:
There can be two kinds of inaccuracies which may creep into the gathered data.
(1) Inaccuracies due to respondent’s bias, and
(2) Inaccuracies due to interviewer’s bias;
The first types of inaccuracies may occur when the respondent is unwilling to co-operate in the interview and may consciously give biased replies. Replies to the same question through personal interviews and mail surveys may be different because the respondents may tend to bias the answers with regard to sensitive questions such as use of deodorants, drinking habits, use of credits, etc.
This bias can checked to a greater extent in personal interviews. Also, in the case of mil surveys, the respondent may be able to understand the question and misinterpret it while answering. Thus, the mail surveys are bound to be full of inaccuracies due to respondent’s misunderstanding and misinterpretation of questions. Most of the questions concerning prestige and living standards are answered in an affirmative manner in the case of mail surveys than in personal interviews.
This inaccuracy can be minimised in the case of personal interviews. Also, in the case of telephone surveys an attempt can be made by the interviewer to reduce the inaccuracies due to respondent. The interviewers are required to be well trained to reduce this type of inaccuracies.
There are inaccuracies which may occur due to interviewer’s conscious or unconscious misinterpretation, style or tone of posing the questions to respondents. Such type of inaccuracies may also occur due to interviewer’s intentional falsification of the interview results (cheating).
These inaccuracies can be checked by training and motivating the interviewers after carefully recruiting and selecting them. An advance warning to investigators may prove to be better. The interviewers may be told in the beginning that their survey results will be checked by meeting some of the respondents. This type of inaccuracies are very common in the case of personal in the case of mail surveys where personal interaction between respondent and interviewer is absent.
Criteria # 4. Amount of Data Gathered:
The telephone survey elicits minimum amount of information. Because it is difficult of hold the respondent for more than five minutes on the telephone as it interferes with his/her home activities. The questions are required to be re-read and explained in telephone survey.
In the case of mail survey, the amount of collected information is lesser because many people do not respond to follow-ups and reminders, personal interview is certainly the best technique for eliciting maximum amount of information from respondents.
This is because in a face-to-face meeting the respondents feel an obligation on their part of answer the questions asked. The respondents may spare a longer period of time to answer the queries of interviewer due to personal interation with the latter.
Criteria # 5. Response Date:
Response rate is described as the percentage of planned interviews that are successfully completed. We can also describe it as the sample size divided by completed interviews.
The non-response may occur due to:
(i) Not at hones, and
(ii) Refusals to co-operate.
The response rate with different survey methods may vary from project to project. It may vary tremendously from 0 to 100 per cent. Generally, the response rate is the highest in the case of personal interviews. It is lesser in telephone surveys and the least in mail surveys.
Criteria # 6. Flexibility:
The personal interviews technique is the most flexible. The interviewer in this case can rephrase the questions can make these understood to the respondents. The interviewer car also use both sight and hearing senses whereas only one sense can also use both sight and hearing senses whereas only one sense can be used in the case of telephone and mail surveys.