This is a preliminary interview, informal, and if you wish, off the record.
The principle methods of investigation will be questionnaires and informal interviews.
Do not try to hold an interview, however informal, while 'on the run'.
If you can do this after an informal interview or visit then so much the better.
If a candidate is a newcomer, this might be done by holding an informal interview.
They might agree to do an informal interview, but they'll never testify.
Given these 'administrative' problems of the informal interview, what advantages and disadvantages does it have?
The informal interview, then, is open to question in a number of ways.
How, then, can the informal interview be used in sociology in an acceptable way?
Two particular functions seem to suit the informal interview.