Surveys

Data Collection

There are three important aspects to consider when conducting a survey: the mode and the organization of the data collection, the sample design, and the construction of the questionnaire. Regarding the first aspect, it is possible to identify four major modes of collection: face-to-face interviews, telephone interviews, self-completed questionnaires, and self-completed questionnaires via the Internet. This typology is essentially based on two dimensions: the presence or absence of an interviewer and the type of support (via telephone or not in the case of the interview, through the web or not in the case of self-completed questionnaire). Currently, researchers use each of these different ways of collection, though in different proportions. However, they have characterized different phases in the history of the survey, reflecting the development of sampling techniques on the one hand and technology on the other. Whereas initially many individuals were interviewed through self-completed questionnaires, mainly via postal service, developments in sampling theory have reduced the number of individuals to be interviewed but have increased the quality of the collection process. The subsequent history of survey was instead marked by technological developments: From the early 1980s, the spread of the telephone, with its advantages in terms of savings and lower invasiveness, has led to an exponential growth in the use of telephone interviews. Lately, the diffusion of the web has revived the self-completed questionnaires. Finally, almost all of these modes of data collections are increasingly computer- aided: the support of the personal computer (PC) is obvious to the self-completed questionnaires via the Internet, but it is pervasive also for telephone interviewing and it is becoming more and more widespread in face-to-face interviews. One of the advantages of using computers is their assistance in running the sequence of questions and checking the compatibility between the codes keyed in and those expected under the coding scheme of responses, so completing the questionnaire becomes faster and the chance of errors decrease.

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