Investigating the Role of Product Line length in Preference Learning, with Mitchell Lovett
We study a rapidly growing CPG category with multiple brand entries and new variety offerings. Consumers learn about true brand quality from advertisements as well as product experience. They also face differing availability of brands and varieties depending on the stores they frequent, inducing heterogeneity in learning rates. Product-line length can affect brand perceptions in two ways. First, a bigger product-line can signal to the consumer that the brand is an expert in the category, affecting brand-specific utility directly. Second, a bigger product-line makes it more likely for consumers to be aware of and interact with the brand. This information can allow the consumer to recognize products that match their tastes. We develop a model of consumer learning and choices that incorporates signals from advertising, product-line length and experience. We apply this model to a unique retail shopper-panel dataset of yogurt purchases across store locations of a major supermarket chain for a random sample of consumers. During our 101-week sample period, 4 brands and 7 new flavors were introduced in Greek yogurt. In the same period, Greek yogurt category share tripled, probability of purchase per store visit quadrupled from 1.8% to 7.8%, and average weekly category-level advertising expenditures increased from $22,000 in the first quarter to $286,000 in the last quarter. Combining this shopper panel purchase information with advertising data, we investigate the relative effects of advertising and product-line on brand learning and category growth.
PhD Program