Competitive Analysis Using a Flexible Demand Specification

Econometric methods can be helpful when one is trying to understand the nature of competition between products in differentiated products industries, an issue that arises in many competition policy contexts. However, misspecification of the consumer demand system can result in biased econometric results and misleading conclusions. We discuss some considerations that go into choosing a demand system specification and suggest that a ‘flexible functional form’ be used. This approach avoids placing restrictions on the demand elasticities. We identify and discuss other issues that arise in the estimation of demand systems. We conclude with an empirical example concerning the calculation of lost profits damages in a patent infringement case. This example demonstrates how using a flexible functional form leads to a substantially more reliable damages calculation than using the particular restrictive functional form that is commonly used to calculate lost profits damages in patent litigation.