economics Practical Magic

To make an economy explode with growth, you don't need to fund every new idea—you just need to fix a few very specific connections between people.

April 13, 2026

Original Paper

Network Design and the Threshold for Explosive Growth

SSRN · 6559450

The Takeaway

Explosive growth is driven by a 'cheat code' within the network of different industries. By identifying and strengthening a handful of central links between specific fields, a country can trigger a chain reaction of innovation that is far more powerful than broad, general investment.

From the abstract

Recent work shows that multi-sector innovation systems can exhibit explosive growth when the spectral radius of the cross-sector feedback matrix exceeds unity. Existing analyses typically treat this matrix as given. This paper instead studies a planner who allocates resources across spillover links and thereby chooses the network topology. The main result is that the marginal effect of strengthening any link on the spectral radius is proportional to the product of the corresponding left and righ