Charles Goodhart, William Claude Dukenfield and Donald Thomas Campbell are three quite different people. Goodhart, born in 1963, is an economist professor emeritus at the London School of Economics. Dukenfield, 1880-1949, better known as W.C. Fields, was an American comedian, actor, juggler and writer. Campbell, 1916-1996, was an American social scientist. What do they have in common? And why do I think that they have some special relevance for development and particularly for what is called ‘managing for results’? It all comes down to the three ‘laws’ named after the three gentlemen.