Self-completion is one of a rarely used methods that sometimes serves as the most efficient way of polling. In whole it comprises two ways of data collection:
1: questionnaires are collected immediately after completion (the questionnaire is self-administered at the presence of the interviewer).
2: questionnaires are collected some time later upon completion (as an option - completion of product consumption diaries, the study of consumer goods baskets).
Self-completion method has a lot of advantages vs. other types of paid surveys:
Some disadvantages of the self-completion methods are: slow moving data collection process and problem with getting completed questionnaires from respondents.