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Rob writes:

I am not an econometrician–I spend my time playing with CGE models–but have to know something about econometrics. Recently I have been reviewing draft papers on a project using detailed tax data in my country–firm-level, matched with individual returns of employees, valued-added tax, import duties, etc.–for the period 2009-2014. A massive and rather unusual database.

It is all good work, but I have two concerns. (Note: I will get to Rob’s second concern at next week’s installment of ‘Metrics Mondays. — MFB.) One is about big data. Many of the researchers report t-statistics and other statistics as if this does not matter. In fact some say they are dealing with the population of firms, in which case my sense is that standard errors say nothing about statistical fit, but maybe about economic significance of relations between means. Even if it is a sample, as n/N becomes closer to 1, sample statistics become problematic.

That is a very interesting question. Let me just rephrase it a bit more broadly to this: What do you do when you are dealing with the population itself instead of dealing with a sample that is representative of a population?

A new paper in the American Journal of Agricultural Economics by Minnesota applied economics alum Travis Smith and some of his University of Georgia colleagues:

The Supplemental Nutrition Assistance Program (SNAP) is the largest nutritional safety net in the United States. Prior research has found that participants have higher consumption shortly after receiving their benefits, followed by lower consumption towards the end of the benefit month. Known as the “SNAP benefit cycle,” this consumption pattern has been found to have negative effects on beneficiaries. We hypothesize two behavioral responses of SNAP participants may work in tandem to drive much of the cycle: (1) short-run impatience—a higher preference to consume today, and (2) fungibility of income—the degree of substitutability between a SNAP dollar and a cash dollar. Using data from the National Food Acquisition and Purchase Survey (FoodAPS), a newly developed nationally representative survey of daily food acquisitions by SNAP households, we find evidence of both behavioral responses. However, the degree of short-run impatience and fungibility of income is found to differ significantly across poverty levels and use of grocery lists to plan food purchases. SNAP households could gain from food purchase planning education.

Last week, Michigan State agricultural economics graduate student Jeff Bloem had a nice post about why he thinks more applied economists should be blogging. And seeing as to how blogging has seemingly done very good things for the careers of those academics who do blog, I can see why Jeff might have chosen the title “Why (More) Applied Economists Should Blog.” In a recent article in Economic Development and Cultural Change, David McKenzie shows that economics blogs play an important role in the dissemination of knowledge, they raise the profile of bloggers and their institution, and they improve the knowledge of the blog’s subject matter for the average reader.

But in a Twitter exchange with Jeff (whom you can follow here), I crystallized my thoughts on the could-should-would of blogging. Though I used to think along the same lines as Jeff–“More economists should be blogging!”–I am now a bit more skeptical.