Mobile app portfolio management and developers? performance: An empirical study of the apple app store

We examine the impacts of mobile app category assortment of developers' app portfolios on app performance in terms of quality and popularity. First, using data from the Apple App Store, we find a negative effect of portfolio diversity on developers' app quality, which is negatively moderated by portfolio size. Second, we uncover spillover effects on app popularity, where existing (new) apps of a developer can influence the popularity of new (existing) apps both within and across app categories (only within the same app category). Importantly, our empirical analyses account for potential endogeneity biases using matching, selection, and simultaneous equations models.