The relationship between quality and market share is likely to depend on how quality is de ned.Virtually all empirical work on this topic has employed the Pro t Impact of Marketing Strategies (PIMS) data base.51 All studies have, therefore, used the same, highly aggregated measure of quality.But if quality is de ned as  tness for use, superior aesthetics, or improved conformance, high quality need not be accompanied by premium prices.Each company in the PIMS survey was  rst asked the following questions: What was the percentage of sales of products or services from each business in each year which were superior to those of competitors?What was the percentage of equivalent products?What was the percentage of inferior products?