Telephone surveys are quickly completed and cost less than personal interviews. It is also relatively easy to implement techniques that increase the representativeness of the sample of respondents. In CATI system, the logic of the interview and the questions to be asked are programmed into a computer. The interviewer reads the questions from the computer screen and answers are recorded directly into the computer. CATI also reduces interviewer error because the computer will not allow incorrect input and handles any necessary adjustment to the questionnaire, such as question that should be skipped or added for a particular respondent (Crask Melvin, et al. 1995)
Sigma Research has special access via CATI and has helped several clients who need survey results quickly.