Diversity of backgrounds and ideas. Nothing is more important on the cutting edge.

Using the historical settlement of migrants as a source of exogenous variation in local ancestry, we show that U.S. counties more exposed to knowledge from a given foreign country absorb substantially more technologies from that country and, in turn, invent significantly more U.S. technologies building on them.

The Causal Effect of Foreign Ideas on U.S. Innovation – Marginal REVOLUTION