The last decades have seen large improvements in digital advertising technology that allowed firms to better target specific consumer tastes. This research studies the relationship among digital advertising, the rise of varieties, and economic welfare. We develop a model of advertising and...

How do political connections affect firm dynamics, innovation, and creative destruction? To answer this question, we build a firm dynamics model, where we allow firms to invest in innovation and/or political connection to advance their productivity and to overcome certain market frictions. Our...

Firm-level productivity differences are big and largely ascribed to ex-ante heterogeneity in the entrepreneurs' growth potential at birth. Where do these ex-ante differences come from, and what can the policy do to encourage the entry of high-growth entrepreneurs? I study empirically and by...