A true postal survey is considered to be a form of in-market research even when it is conducted from South Africa. While it is the least expensive in-market research technique, it is also the most unreliable, especially when undertaking this research over distance in a foreign country.

The principle application of postal surveys should be to help minimise the overall cost of in-market research by reducing the number of personal visits that might be required. However, the technique should seldom, if ever, be used in isolation.

The main advantage of postal surveys is that they are relatively cheap and a wide area and a large number of respondents can be canvassed on a low budget. There are several disadvantages to this research technique, namely:

• The difficulty in selecting a representative sample
• The necessity of keeping the questionnaire short and simple, thus limited the depth of the survey
• The very low response rate usually no greater than 5 per cent
• The bias introduced by the low response rate. Those who do reply usually have a greater interest in the subject than those making up a selection from a random sample