Cost-benefit analysis is remembered today as the tool that tells you whether a bridge or a dam is worth building. But when the U.S. Army Corps of Engineers first used it in the 1930s, the math wasn’t being used to find the right answer, but to survive a turf war. In 1944, a California congressman told the House that “Hitler could not have selected better people to sabotage the American interests” than the analysts behind a rival agency’s report — over a single proposed dam on the Kings River. Both agencies had run the numbers on the exact same reservoir and arrived at opposite answers about what it was even for.
Theodore Porter is Distinguished Professor Emeritus of History at UCLA and winner of the 2023 Sarton Medal, the highest career honor in the history of science. His 1995 book Trust in Numbers essentially created the modern history of quantification as a field of study. In this episode, we trace this history, and he explains why an institution reaching for rigid, rule-bound numbers is usually a sign of weakness.
