Which African country is making the most progress in teaching kids to read by the time they reach third grade? Which language-of-instruction policies are most effective in early literacy teaching? Which country is getting the most children to complete primary school equipped with basic literacy, numeracy, and critical thinking skills?
Guinea worm disease may soon be eradicated from the earth—only a few cases remain. In some eradication efforts, it has become so difficult to find new cases, that data informants are paid more and more (see amounts here) to report the cases that remain: fewer cases, higher reward for finding one. The disease is being wiped out through scarcity-induced reporting incentives.