Understanding the mechanisms of economic development

"I argue that progress in understanding economic development (as in other branches of economics) must come from the investigation of mechanisms; the associated empirical analysis can usefully employ a wide range of experimental and non-experimental methods. I discuss three different areas of research: the life-cycle saving hypothesis and its implication that economic growth drives higher rates of national saving, the theory of speculative commodity storage and its implications for the time-series behavior of commodity prices, and the relationship between economic growth and nutritional improvement. None of these projects has yet been entirely successful in offering a coherent account of the evidence, but all illustrate a process of trial and error, in which although mechanisms are often rejected, unlikely theoretical propositions are sometimes surprisingly verified, while in all cases there is a process of learning about and subsequently modifying our understanding of the underlying mechanisms"--National Bureau of Economic Research web site