In order to formulate an advertising strategy two requisites have to be present: firstly a way of reasoning taking into account all pertinent elements in an orderly fashion and secondly the proper information to fee this scheme so that it develops on a basis of facts and figures and not on thin air. We shall call the first requisite a methodology. It is above all a way of reasoning. We shall call the second a store of data (qualitative for the most part). It is obtained through research. The first object of this paper is to show that this store of necessary data must not be constructed in the light of present research techniques or of what the researcher thinks will be useful later. It must be constructed in the light of the needs of the advertising man when he constructs his advertising strategy in an orderly way.