Relevant market definition continues to be a hotly contested issue in the merger review process. The evidence that can be brought to bear includes econometric estimates of own- and cross-price elasticities of demand based on historical transaction data, market studies that shed light on consumer purchasing patterns, and data that demonstrate the extent to which consumers or buyers can switch from one product or seller to another. However, reliable and relevant data on past purchasing decisions are not always available or sufficient to fully understand consumer demand. In these circumstances, is there an alternative source of data that can be used to assess relevant market definition?

In this chapter from Economics of Antitrust: Complex Issues In a Dynamic Economy, NERA Senior Vice President Dr. Christine Siegwarth Meyer discusses how a properly designed stated preference survey—a survey that asks respondents to choose a preferred product from among a set of alternatives—can inform a relevant market analysis. However, not all surveys yield relevant and reliable data that are admissible in court, and as Dr. Meyer notes, the key is to understand the nature of the product and market at issue and to design a survey that can avoid or reduce problems that can lead to biased or noisy data. Dr. Meyer specifically focuses on discrete choice surveys and the considerations that are involved in developing a well-designed and properly implemented survey.