1

It’s not controversial to say that a historically deep recession ought to be followed by a period of historically strong growth.

Every macroeconomics textbook teaches that changes in GDP can be split into two components: short-run variation driven by aggregate demand and by monetary and financial factors, and a long-run trend driven by population growth and technological change.

While all sorts of things that constrain or inhibit spending can cause temporary dips in production, over time it should converge back to the fundamentals-determined trend. Unless they involve the destruction of real resources — and they don’t — recessions should not have lasting effects. A direct corollary of this textbook view is that the deeper the recession, the stronger should be growth in the following period — otherwise, there’s no way to get back to trend.

The people who are saying that Jerry’s growth numbers are impossible on their face are implicitly saying that that we should expect all output losses in recessions to be permanent. This is not orthodox economic theory, at all. Orthodoxy says that the exceptionally deep recession should be followed by a period of exceptionally strong growth — and if it hasn’t been, that suggests some ongoing demand problem which policy can reasonably be expected to solve.

2

Friedman’s growth estimates are just what you need to get output and employment back to trend.

This point is well made by Matthew Klein. As Klein puts it, this “supposedly ‘extreme’ and ‘unsupportable’ forecast implies American output will return to its previous trend just as Sanders would be finishing up his second term, in the third quarter of 2024.”

As Klein and others point out, the level of GDP projected by Friedman for the end of Sanders’s second term is right in line with what the CBO and other establishment forecasters were saying just a few years ago. I just now was looking at the CBO’s forecasts as of January 2013; they were projecting 4 to 4.5 percent real GDP growth over 2016–17. This is, of course, exceptionally high by historical standards — Paul Krugman says that Jeb Bush was “rightly mocked” by progressives for suggesting he could deliver growth at that level.

But the CBO was making the same prediction and it’s no mystery why — a period of growth well above historical levels is the logical condition of a return of output to trend. By the way, I should emphasize that Friedman’s growth estimates were not derived this way. It’s just a lucky coincidence — if it holds up — that the measures proposed by the Sanders campaign happen to be the right magnitude to close the output gap over eight years.

Similarly, Friedman’s employment numbers (around 277,000 new jobs per month) are indeed way above what we have seen recently. But if you want to get the employment-population ratio back to its 2006 levels by 2024, you need even more than that — about three hundred thousand new jobs per month, by my calculations.

Many respectable economists — including at least one of the CEA signers —  have written that the employment ratio is a better indicator of labor-market conditions than the unemployment rate, and expressed concern about its decline.

A few years ago, Brad DeLong had no doubt that more expansionary policy could raise the employment-population ratio back to 60.8 percent, if not to the pre-recession level of 63 percent: “we could still put 5.5 million more people to work with appropriate demand-management policies.”

To do that by 2024 would imply monthly job growth around 220,000 — less than what Friedman claims for the Sanders proposals, but more than double what the CBO is currently projecting for 2017-2024.

It’s just arithmetic: you can’t raise the employment-population ratio without a sustained period of job growth substantially higher than what we are seeing now. So it makes no sense to talk about that as a goal if you think that faster job growth is not a feasible outcome for policy.

It is true, of course, that the aging of the population implies a long-term fall in the employment ratio, all else equal. But let’s put this in perspective. DeLong, for example, suggests that 0.13 points per year is probably an overestimate of the decline due to demographics. David Rosnick, applying the 2006 employment ratios of various age groups to the population projected for 2026, finds a larger decline due to demographics, on the order of 0.25 points per year.

But even that leaves most of the fall in employment unexplained by demographics. By any standard, there is a lot of room to do better. But we have to agree that this is something that, in principle, demand-side policy can do.

3

In other contexts, it’s taken for granted that more expansionary policy could deliver substantially higher growth.

Anyone who says that the zero lower bound is a constraint on monetary policy, or who suggests that the “natural rate of interest” is negative, is saying that output could be substantially higher given more expansionary monetary policy.

Presumably, this is true for other forms of expansionary policy as well. (In terms of the model beloved by undergraduate textbooks and New York Times columnists: If the preferred point in ISLM space is to the right of the current one, we should be able to get there by shifting the IS curve just as well as by shifting the LM curve.)

Obviously, the transition to that higher level of GDP would involve a period of much higher growth. It would be interesting to ask how fast output would have grown if we’d been able to remove the ZLB constraint in, say, 2010; I suspect the numbers might not look that different from Friedman’s.

Similarly, most participants in this debate agree that the ARRA (American Recovery and Reinvestment Act) stimulus of 2009 was effective, with multipliers above 2.0 for at least some categories of spending. Many also think that it should have been bigger.

If increased government spending could boost output in 2008, then why couldn’t it today? And if the right answer to “How big?” then was “Enough to close the output gap,” why isn’t that the right answer today? Yes, it would be a big number. (Again, it’s a lucky coincidence — if correct — that it happens to be close to what Sanders is proposing.) But so what? If “a trillion has a lot of zeroes” wasn’t a good argument against an adequate stimulus in 2009, then it isn’t one today.

Or again: If we think that austerity explains a big part of poor growth in European countries, we have to at least consider the same might be true here. It would be very good luck, to say the least, if years of feuding between the administration and Republican congresses had somehow delivered exactly the right fiscal balance.

In general, this discussion has been muddied by the fact that the pragmatic choice to delegate demand management to central banks has been turned into an axiom in economic theory. From where I’m sitting, the statement “It would be helpful if the central bank set a lower interest rate” is equivalent, for most macroeconomic purposes, with the statement “It would be helpful if the level of public spending were higher.”

4

Friedman’s projections are unreasonable only if you think the US is already at full employment.

The unstated but central premise of the critics is that we are at or near full employment, so there is no space for further demand policy. Friedman’s paper says that by the end of a second Sanders term, unemployment would be at 3.8 percent. Krugman replies: “It’s possible that we can get unemployment down under 4 percent, but that’s way below any estimates I’ve seen of the level of unemployment consistent with moderate inflation.”

Now here we have an interesting question. Whether we are at full employment today depends, first, on how much you think the fall in the employment-population ratio reflects weak demand as opposed to structural or demographic factors — or in other words, to what extent faster job growth would draw non-workers into the labor market, as opposed to pushing down the unemployment rate. But it also depends on what you think full employment means.

If you believe that any demand-induced acceleration of nominal wage growth will be passed to higher prices, or if you think that price stability should be the sole concern of macro policy, then there will be a hard floor on unemployment, which may not be much lower than where we are today.

But if you think some appreciable fraction of faster nominal wage growth would go to an increase in the wage share (or faster productivity growth) rather than to inflation, and if you think some acceleration in inflation is acceptable (or even desirable), then “full employment” becomes a broad region rather than a sharp line. (I wrote a bit about these issues here.)

In this case there will even be an argument — made by plenty of mainstream people, including some of the ones criticizing Friedman now — that a period of “overfull” employment would be desirable to bring the wage share back up from its current historically low levels. To believe that a 3.8 percent unemployment rate is ruled out by price stability considerations is to claim that faster wage growth cannot raise the wage share, which I don’t think is well supported either theoretically or empirically. (Or that raising the wage share is not desirable.)

Also worth recalling: in the debates around the NAIRU in the 1990s, the general conclusion was that the idea of a hard floor to unemployment below which inflation will rise uncontrollably is not in fact a useful guide for policy.

5

The argument against Friedman’s piece comes down to the claim that the economy is already close to potential.

If this is the case then, yes, claims that increased public spending can achieve large gains in output are delusional. I think this is a useful debate to have, but I’m not sure how the CEA chairs would make the case.

First, again, many of those criticizing Friedman’s numbers have supported the idea of more expansionary policy in other contexts. Second and more fundamentally, the persistent fall in the employment-population ratio and the deviation of output from pre-recession trends seem very hard to explain in “supply” terms. Yes, there are demographic changes, but again, even if you hold the age distribution of the population constant, the employment ratio is still three points lower than at the start of the recession.

That’s a deficit of 10 million jobs. Closing that gap requires an extended period of above average growth, qualitatively similar to what Friedman describes. If you believe that’s impossible, you have to explain why.

Logically, there are a couple possible answers. Either you argue that the earlier estimates of potential GDP were exaggerated, and we were at overfull employment prior to the recession.

If you take this route, you have to be ready to make the case that the country needed substantially slower growth and higher unemployment in the 2000s, despite the noticeable lack of wage growth or rising inflation. Or, you can claim that something happened in 2008-2009 that permanently reduced potential output.

So then, what is the negative technological shock that hit the economy in 2008–9? Is Casey Mulligan right that American businesses have been crippled by the red tape of Obamacare? I don’t think either of those are good options for liberals. Another possibility is to talk about hysteresis and so on — the persistent effects on the labor force and productivity growth from periods of weak demand.

Here you will be on firmer ground — there is plenty of evidence that deep recession inflicts lasting harm on workers and businesses. But this kind of reasoning makes Friedman’s numbers more plausible, not less. Because if weak demand can drag potential output down, strong demand can presumably pull it up.

The bottom line is this. Ten years ago, the CBO expected GDP to be $20.5 trillion (correcting for inflation) as of the end of 2015. Today, it is $18.1 trillion, or about 12 percent lower. Similarly, the employment-population ratio fell by 5 points during the recession (from 63.4 to 58.4 percent) and has risen by only one point during the past six years of recovery.

Either these facts — unprecedented in the postwar period — reflect a shortfall of effective demand, or they don’t. If they do reflect a lack of demand, then there is no reason the expanded public spending and downward redistribution that Sanders proposes cannot close the gap, with a period of high growth while output and employment return to trend. (The fact that such high growth hasn’t been seen in the postwar period is neither here nor there, since there also has been no comparable deviation from trend.)

Alternatively, you may think that the shortfall relative to previous growth rates reflects a decline in potential output. But then you need to offer some explanation of why the growth of the economy’s productive capacity slowed so abruptly, and you need to apply this belief consistently.

I think it’s more reasonable to believe that the gaps in output and employment reflect a demand shortfall. In which case, the Sanders plan could in principle have the kind of results Friedman describes.