What is Contextual inquary

Contextual inquiry (CI) is a user-centered design (UCD) ethnographic research method, part of the Contextual Design methodology. A contextual inquiry interview is usually structured as an approximately two-hour, one-on-one interaction in which the researcher watches the user do their normal activities and discusses what they see with the user.
In this technique users are interviewed while they are doing their tasks.

Advantages
1. Information get by contextual inquiry are highly reliable.
2.Can see user's natural reactions.
3. Information get by contextual inquiry are highly detailed.
4.This is very flexible technique.