In the 1970s, the French government decided to help Africa develop. The lack of lighting had long been identified as an obstacle to development: without lighting, for instance, children could not do their homework at night. Thus the French government decided to subsidize the design and manufacturing of light kits. A small solar panel charged its battery in the day in order to be used at night. The tender was launched, a company that designed robust kits won the contract and the kits were sent to Africa to be distributed. But just a few weeks after the operation was launched, it failed. The kits were not used. Why?