Considering that most surveys use a sample size of at least 100 people, this approach can get very expensive. In recent years, two major developments have given rise to the widespread use of telephone surveys in marketing research. Second, computers have been introduced into the telephone interviewing process. Interviewers now sit in front of a computer screen and read from a pre-programmed questionnaire that appears in front of them. Respondents' replies are recorded directly into the computer system using a keyboard, which saves time in data entry and coding.
Results are immediately available at any point during the survey.
While telephone surveys are much less expensive than in-person interviews, they are usually slightly higher in price than a straight mail survey.