What had I found? The point of my trade models was not particularly startling once one thought about it: economies of scale could be an independent cause of international trade, even in the absence of comparative advantage. This was a new insight to me, but had (as I soon discovered) been pointed out many times before by critics of conventional trade theory. The models I worked out left some loose ends hanging; in particular, they typically had many equilibria. Even so, to make the models tractable I had to make obviously unrealistic assumptions. And once I had made those assumptions, the models were trivially simple; writing them up left me no opportunity to display any high-powered technique. So one might have concluded that I was doing nothing very interesting (and that was what some of my colleagues were to tell me over the next few years). Yet what I saw -- and for some reason saw almost immediately -- was that all of these features were virtues, not vices, that they added up to a program that could lead to years of productive research.
Fortunately, there is a strategy that does double duty: it both helps you keep control of your own insights, and makes those insights accessible to others. The strategy is: always try to express your ideas in the simplest possible model. The act of stripping down to this minimalist model will force you to get to the essence of what you are trying to say (and will also make obvious to you those situations in which you actually have nothing to say). And this minimalist model will then be easy to explain to other economists as well.
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