The geography of U.S. interstate trade barely moved between 1993 and 2022. I construct the first consistent panel of interstate commodity flows from all seven Commodity Flow Survey benchmarks, treating disclosure suppression as censoring, and document the stability four ways. Rank correlations of bilateral flows sit between .95 and .97 across every five-year transition and at .93 over the full 30 years. At least 98.5 percent of 2022 interstate value moves on trading relationships already active in 1993. Most movement in the structure of trade relationships is transitory noise. And the interstate distance elasticity of trade is as steep in 2022 as it was in 1993, notwithstanding the era's logistics revolution and its two largest macroeconomic shocks. Persistence is strongest in differentiated goods—those bound to durable buyer-supplier relationships rather than traded on price—the gradient one would expect if durable relationships, not the goods, hold trade in place. Running a gravity model backwards to solve for the friction it needs to reproduce these flows returns a series too volatile, and too indifferent to documented cost shocks, to be read as transport cost; what a persistent trade matrix asks of the model is persistence on the flow side. Bilateral trade structure is therefore better treated as a slow-moving state of the regional economy than as a fast-adjusting margin—good news for regional accounting, freight forecasting, and the calibration of spatial models, since an older benchmark carries the geography forward and what a fresh survey supplies is the level of trade rather than any rearrangement of its shares.
- The Persistent Geography of Subnational Trade
- Michael L. Lahr (Author) - Rutgers University, Edward J. Bloustein School of Planning and Public Policy
- 2026
- Edward J. Bloustein School of Planning and Public Policy
- English
- Working paper
- 991032323186604646