It's a dirichlet world: Modeling individuals' loyalties reveals how brands compete, grow, and decline

The Dirichlet is one of the most important theoretical achievements of marketing science. It provides insights into the distribution of consumer loyalties and is used widely in industry for benchmarking and interpreting brand performance. The Dirichlet’s implications run counter to some well-entrenched marketing pedagogy and so, unsurprisingly, it has attracted criticism arguing that it cannot adequately reflect the dynamic nature of consumer choice. The authors address these criticisms by discussing how consumer loyalties are manifested and examining whether changes in consumer loyalties do, in fact, disrupt Dirichlet buying patterns. To the best of our discipline’s knowledge, based on extensive empirical and theoretical work, brands compete in a Dirichlet world.