Overall, the findings reported in this paper cast doubt on the
recent trend among economists to dismiss the Solow growth model
in favor of endogenous-growth models that assume constant or
increasing returns to scale in capital. One can explain much of the
cross-country variation in income while maintaining the assumption
of decreasing returns. This conclusion does not imply, however,
that the Solow model is a complete theory of growth: one
would like also to understand the determinants of saving, population
growth, and worldwide technological change, all of which the
Solow model treats as exogenous. Nor does it imply that endogenous growth
models are not important, for they may provide the right
explanation of worldwide technological change. Our conclusion
does imply, however, that the Solow model gives the right answers
to the questions it is designed to address.