Since around 2000, U.S. aggregate productivity growth has slowed and product market (sales) concentration has risen. At the same time, productivity differences among firms in the same sector appear to have risen dramatically. In this paper I propose a rich model of competition and innovation to...

Since around 2000, U.S. aggregate productivity growth has slowed and product market (sales) concentration has risen. At the same time, productivity differences among firms in the same sector appear to have risen dramatically. Sector-level data shows correlations between rising productivity gaps,...

Since around 2000, U.S. aggregate productivity growth has slowed and product market concentration has risen. To explain these facts, I construct a measure of innovativeness based on patent data that is comparable across firms and over time and show that small firms make innovations that are more...

Is there an economic rationale for pronatalist policies? We propose and analyze a particular market failure that leads to inefficiently low fertility in equilibrium. The friction is caused by the lack of ownership of children: if parents have no claim on their children’s income, the private...

Is there an economic rationale for pronatalist policies? In this paper we propose and analyze a particular market failure that may lead to inefficiently low equilibrium fertility and therefore to a need for government intervention. The friction we investigate is related to the ownership of...

In this chapter we revisit the relationship between income and fertility. There is overwhelming empirical evidence that fertility is negatively related to income in most countries at most times. Several theories have been proposed in the literature to explain this somewhat puzzling fact. The...

In this chapter we revisit the relationship between income and fertility. There is overwhelming empirical evidence that fertility is negatively related to income in most countries at most times. Several theories have been proposed in the literature to explain this somewhat puzzling fact. The...