Adoption of innovation follows a bell curve: innovators, early adopters, majority, laggards.
Rogers's 1962 curve, built from Ryan and Gross's study of hybrid seed corn adoption in Iowa. Tarde described the same S-curve in 1890, seventy years earlier.
In practice
- A tool spreads through two enthusiast teams, stalls, and then arrives everywhere at once when procurement standardises on it.
- A neighbourhood's solar panels appear on three roofs, then nothing for two years, then eleven in one summer.