The effect of retail assortment size on perceptions, choice, and sales: Review and research directions

We perform a meta-analytic review of the effect of retail assortment size on consumer perceptions, choice, and retail sales/share using a database comprising of 177 studies obtained from 95 academic papers published during 1970–2021. We define assortment size broadly as the total number of distinct alternatives (options) available to the consumer when he/she makes a choice in a product category. This number of alternatives manifest in the form of a number of brands, number of stock-keeping-units (SKUs), or simply number of items such as different colors or packaging. An increase in assortment size can lead to beneficial effects such as assortment preference, perceived choice satisfaction, confidence, freedom, purchase incidence, sales, and profits, as well as negative consequences such as information overload, increased cognitive effort, choice uncertainty, choice difficulty, and hence choice avoidance. Numerous researchers have reported the effect of assortment size on one or more of these factors. We summarize these effects using a metric called assortment size (net) benefit elasticity by positively valuing the beneficial effects and negatively valuing the harmful effects. Assortment size benefit elasticity is defined as the percent change in net benefit for a 1% change in assortment size. Our meta-analysis reveals that the mean assortment size benefit elasticity across 1936 valid elasticity observations is .082, and this effect is moderated by many study design and environmental factors. We also explore nonlinearity in assortment size effect and whether the effect is different for online vs. offline purchasing. Based on these findings, we list 30 characteristics conducive for assortment addition/deletion and specify several directions for future research.