Does size matter: how product assortment size is related to brand performance

This research examines how product assortment size relates to brand penetration, loyalty, and market share, using data from 34 product categories in the UK and US over time. While assortment size has a strong relationship with brand size, net changes in assortment size are weakly associated with concurrent changes in brand penetration and market share. Assortment size changes also have a weak positive effect on changes in brand loyalty. The research emphasises the importance of brand size and category context when making assortment decisions; and provides managers with assortment size benchmarks. As the first large-scale, multi-country, multi-category longitudinal investigation of product assortment size on brand performance, the paper provides a solid foundation of knowledge including key conditions to underpin theory development related to product assortment.