A simple measure from statistical information theory is proposed to measure the contribution of each independent variable in a multiple regression.

Simulations based on two sets of data are used to assess the impact of combining equations on the accuracy of parameter estimates and their asymptotic standard errors.

Purchasing power parity-based data for gross domestic products are used to assess the affluence of the G-7 countries in the period 1885-1994. A simple Cobb-Douglas model is developed for the eligibility to this Group of Seven.