The personal, face-to-face interview is normally the most reliable method of obtaining data at both the industrial and consumer levels, and is essential where great accuracy in terms of the responses received is required. This method involves the interviewer adopting both a questioning as well as an observing role.

Valuable information can be gained about respondents’ attitudes toward a particular product by observing their reactions and facial expressions as they answer questions during the interview. The opportunity to make such observations is one of the many advantages of the personal interview. Sound knowledge of cultural nuances is essential. Other advantages are:

• The interviewer can cover a wide range of questions
• The researcher has greater control over the interview than (s)he would have talking over the telephone
• Samples or illustrative literature can often persuade the respondents to answer questions more freely than they might if they were being questioned over the telephone or through the medium of a postal questionnaire
• Through the contact established in a personal interview, the researcher can often gain introductions to other potential respondents

Some of the disadvantages of personal interviews include:

• The high cost involved – the researcher can seldom conduct more than three or four interviews per day
• The possibility of interviewer error or bias – this is particularly prevalent where the interviewer asks open-ended questions and must interpret the response
• Consumer research is particularly difficult where the researcher is unfamiliar with the habits and customs of the local population. If consumer interviews need to be performed in a country that is culturally or linguistically incompatible with the researcher’s own country, it may be a good idea to commission a local market research agency or consultant to carry them out