The paper describes a research tool- the Conversion Model -which is now being widely used in the USA, but is still relatively unknown in Europe. Essentially what the model does is to define the people in any given universe according to their relationship with a given brand i.e: for current owners/users of the brand, how strong is the relationship? for current non- owners/users of the brand, is there a basis for building a relationship? The principle of the model is that what needs to be established is not a single dimension of "customer satisfaction" but rather the precise interaction of three separate forces which determine the course of conversion: satisfaction, involvement and ambivalence. What it produces is a statement about customers likely future decision making. This can be particularly useful in product fields where the trends in brand switching may be difficult to read - e.g. consumer durables with 5-7 year replacement cycles. The paper reviews the underlying principles of the model, and describes how it can be employed, using illustrative examples drawn from studies in the car market.