Saturday assorted link

1. And yet so few people are celebrating: “Labor share being higher and corporate profit share being lower as a % of GDP than previously thought”.

You don’t need any other link for today, that explains so much of our intellectual and policy world.

Addendum: On the new Robert Barro gdp double-counting hypothesis, which lies behind all of this, here is a good MR comment:

The algebra is fine as it is, but I take strong issue with the idea that GDP “mismeasures” something. As any decent intro macro course will tells its students, “GDP is not a measure of welfare.” Indeed, the Kuznets quotes that Barro points to are exactly of this nature; we have this high profile GDP number, but it doesn’t do what you want it to do – or at least not ALL the things you want it to.

What Barro does here is construct a new measure – present discounted value of consumption – and shown how it relates to GDP (and GDP’s present discounted value). In addition, he provides a capital income / labor income decomposition for both measures (GDP having such an exact decomposition because of constant returns to scale, Euler’s identity for homogenous functions, and marginal-value input prices). He then says present discounted value of consumption, and its associated decompositions, are “right” while the other the construction GDP is “wrong” and thus gives “misstated” decompositions. Of course, “right/wrong” and “correct/incorrect” begs the question – right about WHAT? Correct for WHAT?

Barro says that in present discounted value terms GDP “double counts” investment. The “double counting” is only relative to how things are calculated for the present discounted value of consumption. This just reflects the fact that GDP counts production, while consumption only counts consumption. Market clearing, saving, and no storage imply that in every period consumption will be less than production. Specifically, looking at present values, future consumption in part reflects past savings i.e. past investments. GDP counts the production from the investment part (e.g. making the car) and the consumption part (e.g. driving the car), while consumption only counts the consumption part. If what you’re after is welfare – sure only count consumption. If what you’re after is production, well then you count production. Absolutely, GDP is higher than consumption. All Barro has done is given a more precise statement of how much bigger, in a PDV sense, GDP will be than consumption.

Noting that the “capital” share of GDP and the “capital” share of consumption are different is more word games. Indeed, assigning similar names to decompositions of different constructs is completely arbitrary. Barro doesn’t explain why the “capital share” of one thing is more important than the “capital share” of some other thing. In practice, we care about the “capital share” because it tells us something about the structure of the economy – i.e. with Cobb Douglas the capital share of GDP is used to calibrate the alpha parameter. Skimming the paper, its not immediately obvious what the structural parameter linked to the “capital share” of PDV consumption is, but I wouldn’t be surprised if its just alpha/2. Ok, the “capital share” of something different concept spits out a different number. For an RBC/neoclassical type, not thinking about the structural parameters is an obvious mistake…

More interesting than the LEVEL of any value is how these values change over time, and what this implies for the changing structure of the economy. Barro’s attempt to say the level of the capital share is “wrong” misses the point – we aren’t after the capital share per say, we’re after alpha. And since the two “capital shares” are proportional, a rising GDP capital share is the same as a rising PDV consumption capital share. The mystery continues, just with scaled down numbers…

But I think that means Barro is basically correct.


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