Abstract
It is common that the discovery or development of a statistical finding precedes its implementation, but in certain cases this is not true. The development of the Theil BLUS technique is a specific example of a two-way relationship between econometric theory and software design. In particular, the fact that the sum of squares of the N-K BLUS residuals is equal to the sum of squares of the N OLS residuals was first observed experimentally and subsequently proved in theory.