Fig. 3. Diagram of causal arguments.

The association of environmental prestige with greater scientific productivity (Fig. 1A) is explained by greater available funded labor at elite institutions (Fig. 1, C and D), which drives larger faculty group sizes, even accounting for prestige (Fig. 2, A and B) and predicts both group productivity and total productivity. Faculty group size itself has a natural and tight relationship with group productivity, independent of prestige (Fig. 2C) because group member productivity itself is essentially independent of prestige (Fig. 1A). Last, increased group productivity can explain most of the prestige-productivity effect in disciplines with collaboration norms (Fig. 1B). A full causal diagram with confounders is provided in the Supplementary Materials (fig. S5).