Development of competition indicators in the Norwegian general practice: Constructing a postal code-specific Herfindahl-Hirschman index applying STATA software

The purpose of this text is to describe a procedure that can be used to construct a Herfindahl-Hirschman index of market concentration based on the following two pieces of information: <p> <p> a) An output measure of individual producers located in areas identified with a postal code. <p> b) A matrix containing information about the distances between the (centers of) the areas defined by postal codes. <p> <p> The examples presented in this text are from the market for general practitioners’ services in Norway, but applying the suggested procedures to other output measures should be straight forward. The STATA commands necessary to construct the index are provided. <p>