Q.Explain the various methods of collecting primary data.

Primary data can be gathered by several methods, each trading accuracy against cost and coverage.

The five standard methods are direct personal investigation, indirect oral investigation, local correspondents, the mailed questionnaire, and schedules sent through enumerators.

Primary data is collected first-hand by one of the following standard methods:

1. Direct personal investigation (direct interview). The investigator personally questions each informant face to face — highly accurate and reliable, doubts cleared on the spot, but costly, slow, suited only to a small field, and open to personal bias.
2. Indirect oral investigation. Third parties (witnesses / persons connected with the matter) are questioned instead of the informants themselves — used when informants are unwilling or the matter is sensitive; several witnesses are cross-checked because answers may be biased.
3. Information through local correspondents (agents). Local agents collect and send data in their own way — cheap and giving wide, continuous coverage (used by newspapers, government departments), but less accurate as it depends on each correspondent's judgement.
4. Mailed questionnaire method. A printed list of questions is mailed to informants who fill it in themselves — economical and wide-reaching, but works only with literate informants, suffers non-response, and cannot clear doubts.
5. Schedules through enumerators. Trained enumerators carry a schedule to informants, ask the questions and record the answers — wide coverage with personal-contact accuracy, works with illiterates, high response, but the most expensive method (used in the census).

Note: in the questionnaire method the informant fills the form; in the schedule method the enumerator fills it.

The most common slip is confusing the questionnaire method with the schedule method — remember the informant fills the questionnaire, whereas an enumerator fills the schedule. Also, do not omit indirect oral investigation, which is frequently tested.