A pre-test study set out to predict which of three versions of a new Lever Brothers product was most likely to be successful. All three products were test-marketed. The paper reports this case history and discusses the following: The role of pre-testing in this context, and the principle of the limited research objective. The kind of new product stimulus that informants can meaningfully respond to in the pre-test situation. The use of experimental research designs, and the kinds of variable that can be researched through them. A comparison of pre-test predictions and test market results, illustrating the detailed accuracy in this particular case of a certain type of comparative measure. The high difference in sales attributable to the variables under study.