Using Duplication of Purchase Analysis to Reveal Brand Sub-Markets: The Case of OTC Pain Relief Tablets

This study analyzes the extent to which the top 8 brands in the US OTC pain relief tablet market share their buyers with each other. The study uses the Duplication of Purchase Analysis method. It shows that brands in this market overall follow the Duplication of Purchase Law, namely that each brand shares its buyers with other brands in-line with how big those other brands are. Furthermore, several ‘partitions’ are identified: Aspirin brands share buyers more with each other than expected, so do Ibuprofen brands but to a lesser extent.