Kerala fishermen phoned ahead to find where their fish were wanted

Kerala's sardine fishermen faced a pure information problem with brutal consequences. At sea, with no way to communicate, a boat had to pick a landing market blind. If too many boats guessed the same port, the price collapsed and unsold fish — highly perishable, no storage — were dumped into the sea. Meanwhile a market a few kilometres up the coast might have buyers and no fish. Prices varied wildly between beaches on the same morning, waste was routine, and both fishermen and consumers lost.

Between 1997 and 2001 mobile phone service rolled out along the Kerala coast. Because coverage arrived in stages by region, economist Robert Jensen could observe what happened as boats gained the ability to call ahead — a natural experiment in what information alone is worth.

Fishermen began phoning multiple beach markets from the boat before landing, comparing prices and sailing to wherever demand actually was — replacing a blind guess with a market survey conducted at sea. Jensen's study, published in the Quarterly Journal of Economics, documents the result: price dispersion between markets collapsed, waste was essentially eliminated (unsold catch went to virtually zero), and prices converged toward the Law of One Price.

Phoned multiple beach markets from the boat before landing, comparing prices and sailing to where demand was, replacing a blind guess with a real-time market survey.

The catch and buyers existed, but boats had to choose a market before knowing prices, causing misallocation.

Phones moved the decision point to after price information arrived, so supply could route to actual demand.

With supply matching demand, arbitrage-driven gluts and shortages disappeared, cutting waste to near zero.

Both fishermen and consumers gained, making adoption self-reinforcing rather than zero-sum.

When suppliers must commit before seeing demand, give them a cheap way to check demand first; it can eliminate waste without adding capacity.

Price dispersion between beach markets collapsed and waste was essentially eliminated, with both fishermen's profits and consumer welfare rising (Jensen, QJE 2007). The most-cited empirical demonstration that information access alone creates large welfare gains — foundational to ICT-for-development policy, though later fieldwork questioned how much of the effect was really price-checking.