Three econometricians are out hunting. They spot a stag. Given this is a story about economists let us assume it is a deaf stag.
The first econometrician aims, fires but misses to the left by a metre. The second econometrician takes aim, fires and also misses - but by a metre to the right.
The third econometrician does not take aim or fire. Exultant, he cries out "Nailed it!"
Visually this joke appears thus: