The information necessary for the marketing decision making is generally issued from many chronological and spatial independent systems. It is the case for SECODIP where we find several information systems consumer's panels, retailer panel, advertising expenditure research, ad hoc surveys (schema 1). The main object of the SECODIP data bank is to integrate all these data at the basis. The general organisation of the new system is resumed in the schema 2. We can see that this new system does not take the place of the present one, but completes it. The two main ideas of this new system are the following: 1) The integration of the data is realised at the basis, on the consumption unit (the household); 2) The system restores a specific information adjusted to a given demand itself function of the marketing decision.
This paper sets out to illustrate by example the use of a Motorists Diary Panel covering both the petrol and motor oil markets. We have taken, two separate marketing activities which have had a profound effect on the market and a third example illustrating a simple application of panel data. Taking first the basic use of panel data, we have a simple examination of the pattern of purchase over a long period which illustrates how the brand structure of a market changes during the course of a year.
Consumer panels have by this time become a relatively classical device for investigating buying habits in the field of mass-consumption goods: it occurred to us that a rather different type of panel could be devised with a view to checking on sales of less popularised products. The foundations of the SOFRES Panel started to be laid in the late Sixties, on the basis of new mailing questionnaires techniques which led to renewed interest in the psychological forces underlying refusal or acceptance of response to ad hoc questionnaires. The special technique behind the SOFRES Panel was thus built up by reference to two sources of practical experience: - conventional consumer panels, - the ad hoc questionnaire.
It has been stated that up to now the basis for panel investigations has been the decision for the purchase of a product. It was attempted to explain these decisions either by the price situation, the competitive situation or the socio-demographic structure . Excluded from these considerations was the general behaviour of the types of outlets as influential factor on buying decisions. This analysis tries to demonstrate this further starting point. It would be desirable to develop these attempts in further discussions.
The advantages of consumer panel data therefore extend way beyond its ability to provide comprehensive brand share data where other methods suffer from Inadequate coverage, to tell us something about the numbers of people buying as well as the quantity bought and to analyse the data by people as well as by area and shop type characteristics. The major value of a consumer panel can only be extracted when one stops regarding It as a measure of group behaviour within defined time periods and starts regarding it as a measure of individual behaviour over time.
The objectives of operating consumer panels are the registration of consumer behaviour and the changes in this behaviour. There is an increasing interest of marketing people for information on changes in behaviour, when and where they occur, how they come about and which categories of people are most responsible for these changes. Analysis and evaluation of this type of information may uncover trends in or even laws of behaviour, which can be of great importance for the decision making process in marketing..
The Baby Panel is an example of the panel technique being very successfully adapted to measure a market where buyers remain for a relatively short period of time and yet during that time their characteristics change dramatically. One might summarise panel techniques as offering two different types of measurement: - Firstly the study of changes over time in the behaviour of individuals or groups of individuals. Secondly the study of changes in the pattern and trends of the total market over time. This paper describes very briefly how these objectives have been met by the Baby Panel since January 1967 and it concentrates on the problems we have encountered, some of which have been solved satisfactorily, others, at present defying really satisfactory solutions.
The developments that led to the establishment of an individuals panel based on an existing housewife panel, and its operation, have been described. Experiences with the panel have been outlined which illustrate the advantages of pre-coding of diaries and despatch of individual diaries to segments of the population, together with the flexibility that can be achieved in the type of information that can be collected from such a panel
The issue of standardising data collection methods in panel research is made the more difficult and at the same time the more important by the fact that there are very few agreed upon principles in panel design. Therefore, if the current interest in making panel data comparable will result in the emergence of some basic guidelines for panel design, this would be beneficial to the whole field of panel research. In this paper, only a small, albeit important aspect of panel design will be discussed ~ namely that of panel composition.
After this introduction the discussion followed by talking about the validity in the panel results (over-representing versus under-representing) . Are the members writing down everything? This is one of the key-problems when talking about the validity. For major acquisitions (dresses, coats, etc.) this problem is not looked upon as being very big. The main problems arrive when we come to more frequent purchases, particularly to very individual products (stockings, underwear etc.). This part of the discussion led to the final point where, it particularly from the client's side, was stressed that the panel institutes do too little in trying to evaluate the data. Their eyes are too little critical, besides the fact that their product development is not sufficient. From the institutes side it was stressed that the clients in many cases are too much price conscious, which can mean that there is too little money to improve the validity of the results, to carry out experiments etc. The panel techniques in itself have so many advantages compared to other research techniques that their market share should be higher than it is to-day.
In this document we describe the basic structure of buyer behaviour for a certain frequently-bought branded product. The purpose is to illustrate, in terms of a real-life but coded example, the analysis of brand-switching, of heavy buyers, of penetration growth and of repeat-buying loyalty which are provided by our "Loyalty Reports" service.
The aspects of panel developments I shall examine are: 1. Panel size and composition; 2. The nature of the information collected and the collection method; 3. Report content, design and delivery; 4. Accuracy of the data; 5. Data analysis methods.