というNBER論文をエスター・デュフロが上げている(原題は「The Economist as Plumber」)。元はAEAのイーリー講演(cf. 動画)。

As economists increasingly help governments design new policies and regulations, they take on an added responsibility to engage with the details of policy making and, in doing so, to adopt the mindset of a plumber. Plumbers try to predict as well as possible what may work in the real world, mindful that tinkering and adjusting will be necessary since our models gives us very little theoretical guidance on what (and how) details will matter. This essay argues that economists should seriously engage with plumbing, in the interest of both society and our discipline.


Economists are increasingly getting the opportunity to help governments around the world design new policies and regulations. This gives them a responsibility to get the big picture, or the broad design, right. But in addition, as these designs actually get implemented in the world, this gives them the responsibility to focus on many details about which their models and theories do not give much guidance.
There are two reasons for this need to attend to details. First, it turns out that policy makers rarely have the time or inclination to focus on them, and will tend to decide on how to address them based on hunches, without much regard for evidence. Figuring all of this out is therefore not something that economists can just leave to policy makers after delivering their report: if they are taking on the challenge to influence the real world, not only do they need to give general prescriptions, they must engage with the details.
Second, details that we as economists might consider relatively uninteresting are in fact extraordinarily important in determining the final impact of a policy or a regulation, while some of the theoretical issues we worry about most may not be that relevant. This sentiment is well summarized by Klemperer (2002) who presents his views on what matters for practical auction design, based on his own experience designing them and advising bidders: "in short," he writes, "good auction design is mostly good elementary economics," whereas "most of the extensive auction literature is of second-order importance for practical auction design."

以下は、「なぜ経済学者は良き配管工となるか(Why economists make good plumbers)」と題された第3節の結論部。

To summarize, economists have the disciplinary training to make good plumbers: economics trains us in behavioral science, incentives issues, and firm behavior; it also gives us an understanding of both governments and firms as organizations, though more work probably remains to be done there. We economists are even equipped to think about market equilibrium consequences of apparently small changes. This comparative advantage, along with the importance of getting these issues right, make it a responsibility for our profession to engage with the world on those terms.


Many of us chose economics because, ultimately, we thought science could be leveraged to make a positive change in the world. There are many different paths to get there. Scientists design general frames, engineers turn them into relevant machinery, and plumbers finally make them work in a complicated, messy policy environment. As a discipline, we are sometimes a little overwhelmed by "physics envy," searching for the ultimate scientific answer to all questions - and this will lead us to question the legitimacy of plumbing. This essay is an attempt to argue that plumbing should be an inherent part of our profession: we are well prepared for it, reasonably good at it, and it is how we make ourselves useful. A feature unique to economics that scientists, engineers, and plumbers all talk to each other (and in fact are often talking to themselves - the same economist wearing different hats). This conversation should continue: it is what what will keep us relevant and, possibly, honest.

*1:cf. これ