2. Telephone interviews

Fast cheaper used by 'sales marketing', shorter attention span. Hard to ask personal questions, good for panel results, better for industrial 'business to business'.

3. Postal questionnaires

Widespread, cheap, honesty increases if on an anonymous basis, 67. return rate low must be shorter and more precises/definite, can incentives the response.

4. Panel surveys

Used over a period of time, quite detailed. Used to monitor advertising.