Comparative product testing, the main activity of consumer organizations, can be defined as determining if, and to what degree, features which are relevant for consumers, are found to be constituent characteristics of a representative number of brands and types of a certain product. Afterwards, the compared test results (of the different products) are published simultaneously, and the prices of the products are listed (SER, cited in (Box79)). This definition of comparative product testing emphasizes the relation between consumer and product, or, to be more precis, it relates the consumer's needs and consumer behaviour to the features of one or more products.
Comparative product tests aim at providing objective and independent information (Box79) . Objectivity is guaranteed by the consumer associations: general norms and standard procedures of measurement are used as much as possible and research is done either in-house or contracted to independent institutions. The information is to be obtained independently of producers or suppliers and only the consumers' interests matter. Consumer organizations show their objectivity by not including advertisements in their magazines and by stressing their independent and even critical attitude towards the industry (Box79).
The following list (Willenborg85) provides some characteristics of (the results of) comparative product tests:
The testing activities of the consumer organizations concern, on the one hand, product oriented and, on the other, consumer oriented research. This latter type presupposes that the consumer is directly involved, mostly by means of interviews or questionnaires. Generally, however, comparative product tests, as performed by consumer associations, consist only to a small extent of consumer research. According to (Box79), the reason for this is that the organizations hold the opinion that consumer research yields little and that the results may vary to such a degree that it would be impossible to conclude anything from it.
Therefore, the most important object of research for the consumer organizations is the technical and economic functionality of products as a measure for the satisfaction of needs by means of consumption (Kanis88) . The functionality of a product results from the interaction between the product's specifications, its user and its environment (Siderius89) . Examples of environmental variables are the detergent when testing washing-machines and the floor-covering when testing vacuum cleaners.
The test results, that is, the neutral product information published by consumer organizations, can be regarded as having two important functions (Box79): providing a better view of the market supply (horizontal analysis) and a more transparent market (vertical analysis). The first function implies presenting products and brands to consumers; the second implies supplying comparative information on quality aspects of the products. In this way, neutral product information will help the consumer to select a product that fulfills their (unconscious) needs.