Advantages:
(a) Personal interview
1. Highest response rate
2. Allows use of all types of questions
(b) Mailing questionnaire
1. Least expensive
2. Only method to reach remote areas
3. No influence on respondents
4. Maintains anonimity of respondent
5. Best for sensitive questions
(c) Telephones
1. Relatively low cost
2. Relatively less influence respondents
3. Relatively high responserate.
Disadvantages:
(a) Personal interview
- Most expensive
- Possibility of influence respondents
(b) Mailing questionnaire
- Cannot be used by illiterates
- Long response time
- Does not allow explanation of unambiguous questions
- Reactions cannot be watched.
(c) Telephones
- Limited use
- Reactions cannot be watched.
- Possibility of influencing respondents
