Educational policies deserve to be programmed not only with a view to improving education in the widest sense, but also in order to ináuence the inco… - Jan Tinbergen

The two preponderant forces at work are technological development, which made for a relative increase in demand and hence in the income ratio... and increased access to schooling, which made for a relative decrease.

For some queer and deplorable reason most human beings are more impressed by words than by figures, to the great disadvantage of mankind.

The advantages of models are, on one hand, that they force us to present a "complete" theory by which I mean a theory taking into account all relevant phenomena and relations and, on the other hand, the confrontation with observation, that is, reality.