Robert Solow on Piketty

Solow writes,

if the economy is growing at g percent per year, and if it saves s percent of its national income each year, the self-reproducing capital-income ratio is s / g (10 / 2 in the example). Piketty suggests that global growth of output will slow in the coming century from 3 percent to 1.5 percent annually. (This is the sum of the growth rates of population and productivity, both of which he expects to diminish.) He puts the world saving / investment rate at about 10 percent. So he expects the capital-income ratio to climb eventually to something near 7 (or 10 / 1.5). This is a big deal, as will emerge. He is quite aware that the underlying assumptions could turn out to be wrong; no one can see a century ahead. But it could plausibly go this way.

…The labor share of national income is arithmetically the same thing as the real wage divided by the productivity of labor. Would you rather live in a society in which the real wage was rising rapidly but the labor share was falling (because productivity was increasing even faster), or one in which the real wage was stagnating, along with productivity, so the labor share was unchanging? The first is surely better on narrowly economic grounds: you eat your wage, not your share of national income. But there could be political and social advantages to the second option. If a small class of owners of wealth—and it is small—comes to collect a growing share of the national income, it is likely to dominate the society in other ways as well. This dichotomy need not arise, but it is good to be clear.

Both Tyler Cowen and Solow make the same point about wages, but they do so subtly. Let me be blunt: Piketty’s nightmare scenario, in which capital accumulates and has a high return, is a terrific scenario for wages in absolute terms. If workers care about what they can consume, as opposed to the ratio of their net worth to that of the capital owners, they would hate to see any policy that might interfere with the high rates of investment that Piketty is envisioning. Note, however, that I personally would not concede that the distinction between workers and capital-owners is as clear-cut as it is in the Solow growth model.

The tone of Solow’s review is generally laudatory. It also is by far the clearest explanation of Piketty’s argument that I have read. It reflects Solow’s command of the logic of economic growth as well as his abilities as a teacher.

I think that Solow arrives at a higher evaluation of the book than I would for two reasons. First, Solow gives Piketty the benefit of the doubt on nearly every uncertain issue. For example, on the crucial assumption that Piketty makes that the rate of return on capital remains steady even as the capital-income ratio creeps ever higher, Solow writes,

Maybe a little skepticism is in order. For instance, the historically fairly stable long-run rate of return has been the balanced outcome of a tension between diminishing returns and technological progress; perhaps a slower rate of growth in the future will pull the rate of return down drastically. Perhaps. But suppose that Piketty is on the whole right.

On another issue, the fact that inequality is high between different workers, not just between workers and capitalists, Solow offers a hand-waving defense of Piketty. Solow writes,

Another possibility, tempting but still rather vague, is that top management compensation, at least some of it, does not really belong in the category of labor income, but represents instead a sort of adjunct to capital, and should be treated in part as a way of sharing in income from capital…

it is pretty clear that the class of supermanagers belongs socially and politically with the rentiers, not with the larger body of salaried and independent professionals and middle managers

To this, I would say: why draw the line at supermanagers? Why not say that the salaries of college professors that are paid out of university endowments are “a way of sharing income from capital”? The way I look at it, the amount of income that does not represent “a sort of adjunct to capital” (including human capital) is miniscule, perhaps less than 1 percent of GDP.

My second disagreement with Solow is that he, like Piketty, omits any discussion of risk as a component of “r.” In that regard, Tyler Cowen’s skeptical review better accords with my own thinking.

The way I see it, Piketty and Solow work with models that incorporate homogeneous workers (with no differences in human capital) and homogeneous capital (with no differences in ex ante risk or ex post returns). The real world is so far removed from those models that I simply cannot buy into the undertaking.

Greg Mankiw Quotes a Professor of Social Work

Greg cites a piece in the NYT by Mark R. Rank. Before I get to that, let me read to you from Rank’s bio page at Washington University.

Mark R. Rank is widely recognized as one of the foremost experts and speakers in the country on issues of poverty, inequality, and social justice. . .

His next book, “One Nation, Underprivileged: Why American Poverty Affects Us All,” provided a new understanding of poverty in America. His life-course research has demonstrated for the first time that a majority of Americans will experience poverty and will use a social safety net program at some point during their lives.

He is currently completing a book with his long-time collaborator, Thomas Hirschl of Cornell University, entitled, “Chasing the American Dream: Understanding the Dynamics that Shape Our Fortunes.” It explores through a multi-methodological approach the nature of the American Dream and the economic viability of achieving the Dream. The book is designed to shed light on the tenuous nature of the American Dream in today’s society, and how to restore its relevance and vitality.

The NYT piece is based on the latter book. In it, Rank writes,

It turns out that 12 percent of the population will find themselves in the top 1 percent of the income distribution for at least one year. What’s more, 39 percent of Americans will spend a year in the top 5 percent of the income distribution, 56 percent will find themselves in the top 10 percent, and a whopping 73 percent will spend a year in the top 20 percent of the income distribution.

…Likewise, data analyzed by the I.R.S. showed similar findings with respect to the top 400 taxpayers between 1992 and 2009. While 73 percent of people who made the list did so once during this period, only 2 percent of them were on the list for 10 or more years. These analyses further demonstrate the sizable amount of turnover and movement within the top levels of the income distribution.

Some comments:

1. Many people experience having an income below the poverty line for a short period of time. However, I am not sure that one can conclude from this that they “experience poverty.” Think of graduate students, or people who experience a spell of unemployment but otherwise are able to hold a job.

My first year after graduate school, when I got married and started working at the Fed, my salary made us eligible for Montgomery County’s low-income housing assistance (we did not make use of that eligibility). Our household income probably did not exceed the median household income until my 8th or 9th year out of grad school.

2. Similarly, many people experience windfalls. We broke into the top 20 percent for exactly one year, the annus mirabilis 1999 when my Internet business got sold.

3. You would think that the perspective of a social work professor on income dynamics would be less valuable than the perspective of, say, Thomas Piketty. Yet it is possible that Rank’s new book might have something to add, because he is working with longitudinal analysis that follows the same people over time, rather than working with a time series of cross-sections and writing down a model that treats households (really, just abstract social classes) as persistently occupying the same place in the income distribution.

4. I have started reading Chasing the American Dream, and I may write a review. It is much closer to what you would expect from a professor of social work than what you would expect from, say, Greg Mankiw. The book treats economic position as being determined by race and social class.

I’d Connect These Data Points

1. From Inside Higher Ed:

The Maryland Higher Education Commission is cracking down on institutions that provide distance education to students in the state. But the commission has a problem: It doesn’t know who those distance education providers are.

The commission last month fired off letters addressed to presidents and provosts of institutions that offer fully online programs (seen at the bottom of this article), asking them to self-report if they enroll students in Maryland.

“As of July 1, 2012, higher education institutions offering fully online education to Maryland residents must submit an application to register with the Maryland Higher Education Commission,” the letter reads. “A review of the Integrated Postsecondary Education Data System has revealed that in 2012 your institution offered fully online programs and enrolled Maryland residents. If any of your current students are Maryland residents and are enrolled in fully online programs, the aforementioned regulation applies to your institution.”

2. The Washington Post reports,

The University of Maryland wants to build an 11-story, $115 million luxury hotel and conference center across from its main entrance in College Park.

The connection I would make is that both stories indicate the priority that Maryland’s state higher education authorities place on education.

Voluntary Private Cooperation

Mike Munger makes the case.

Poverty is what happens when groups of people fail to cooperate, or are prevented from finding ways to cooperate. Cooperation is in our genes; the ability to be social is a big part of what makes us human. It takes actions by powerful actors such as states, or cruel accidents such as deep historical or ethnic animosities, to prevent people from cooperating. Everywhere you look, if people are prosperous it’s because they are cooperating, working together. If people are desperately poor, it’s because they are denied some of the means of cooperating, the institutions for reducing the transaction costs of decentralized VPC.

I think it helps if people understand this. However, progressives will argue that we cannot have VPC without government and that, moreover, government can improve VPC.

Pointer from Don Boudreaux.


While on a Sunday stroll, I encountered Jerry Muller, author of The Mind and the Market, among other works. He asked me what I thought about “short-termism.” Mostly, I think that it is a difficult concept to pin down.

I guess my working definition would be that short-termism is a bias among executives to forego long-term opportunities in order to achieve short-term profit objectives.

But how would you measure it? What observations would confirm it?

For example, I might argue that, at today’s low long-term interest rates, a nuclear power plant looks like a high net-present-value investment for a utility company. Does their failure to invest in nuclear power plants reflect short-termism? Obviously, it is more complicated than that. There are regulatory barriers, site licensing barriers, and there is economic risk–suppose that ten years from now solar power becomes so inexpensive that the price of electricity no longer provides a decent return on the up-front investment? Not to mention the risk that the plant will have something wrong, or that the nuclear waste will be a problem, or some other risk.

The point is, it is very hard to separate pure time preference from risk when it comes to real-world investments.

Some other thoughts:

1. For the economy as a whole, most pundits think that the big long-term investment opportunities are in energy, computers/communications/robotics, nanotechnology, and biotechnology. My impression is that biotech is perhaps being held back by regulatory issues. But otherwise, I get the sense that investment is pretty active. Google certainly is making some long-term investments.

2. Sometimes, the financial crisis is blamed on short-termism. But there is very little evidence that the banks knew that they were making short-term profits that were going to turn sour in the long term. Instead, it seems that they believed that things were fine, both short term and long term.

3. If you were going to advise a firm to sacrifice some short-term profits in order to undertake long-term investments, which firm would that be? What investment should it make? Can you be confident that it is short-termism rather than concern about risk that is inhibiting the investment?

I’d Connect These Data Points

1. From Atif Mian and Amir Sufi.

We are now five full years from the end of the recession (if you buy NBER dating). And housing starts are still below any level we’ve seen since the early 1990s!

Pointer from Mark Thoma.

2. Shaila Dawan writes,

Nationally, half of all renters are now spending more than 30 percent of their income on housing, according to a comprehensive Harvard study, up from 38 percent of renters in 2000. In December, Housing Secretary Shaun Donovan declared “the worst rental affordability crisis that this country has ever known.”

Pointer from Tyler Cowen.

By the way, I saw this coming, and so I made a big investment last year in several companies that own and manage apartments. The performance of these investments was terrible, particularly when compared with the overall market. Go figure.

John Cochrane vs. Financial Intermediation

He writes,

demand deposits, fixed-value money-market funds, or overnight debt must be backed entirely by short-term Treasuries. Investors who want higher returns must bear price risk. Intermediaries must raise the vast bulk of their funds for risky investments from run-proof securities. For banks, that means mostly common equity, though some long-term or other non-runnable debt can exist as well. For [money-market?] funds, or in the absence of substantial equity, that means shares whose values float and, ideally, are tradable.

I suppose Murray Rothbard would have liked this.

My own aphorism about financial intermediation is that the nonfinancial sector wants to issue risky, long-term liabilities and to hold riskless, short-term assets, which the financial sector accommodates by doing the opposite. If that aphorism is correct, then Cochrane’s vision involves getting rid of financial intermediation.

I suspect that the optimal amount of financial intermediation is not zero. However, I suspect that it is not as much as we get in a world in which there is deposit insurance, too-big-to-fail guarantees, and tax advantages of leverage. Here, Cochrane’s tactical approach is interesting.

Pigouvian taxes provide a better structure for controlling debt than capital ratios or intensive discretionary supervision, as in stress tests. For each dollar of run-prone short-term debt issued, the bank or other intermediary must pay, say, five cents tax. Pigouvian taxes are more efficient than quantitative limits in addressing air pollution externalities, and that lesson applies to financial pollution. By taxing run-prone liabilities, those liabilities can continue to exist where and if they are truly economically important. Issuers will economize on them endogenously rather than play endless cat-and-mouse games with regulators.

The way I put it is that you cannot make financial institutions too regulated to fail. So instead of trying to make financial institutions harder to break, try to make them easier to fix. This means taking away the incentives to adopt unstable financial structures. Cochrane would go further and penalize unstable financial structures using taxes.

Meanwhile, Peter Wallison warns that the command-and-control approach to regulation has a logic of ever-widening jurisdiction.

Yuval Levin on Scientism and Skepticism

He writes,

But understanding human limitations does not mean we can overcome them. It only means we can’t pretend they don’t exist. It should point us toward humility, not hubris. And in politics and policy, understanding the limitation that Klein highlights should point us away from technocratic overconfidence and toward an idea of a government that enables society to address its problems through incremental, local, trial-and-error learning processes rather than centrally managed wholesale transformations of large systems.

I suggest reading the whole thing. I could have picked about any paragraph at random to excerpt.

Greg on Greg

Meaning Cochran on Clark.

If moxie is genetic, most economists must be wrong about human capital formation. Having fewer kids and spending more money on their education has only a modest effect: this must be the case, given slow long-run social mobility. It seems that social status is transmitted within families largely independently of the resources available to parents.

Pointer from Jason Collins.