A Review of Mian & Sufi’s House of Debt

Lawrence Summers, a Professor of Economics at Harvard University and a Financial Times columnist, hailed Atif Mian & Amar Sufi’s book as ‘the most important economics book of the year’. The book was published in 2015 by the University of Chicago Press. This is a very readable book on issues of debt (particularly household debt in America), determination of activity levels, and on how to do good economics.

        Mian & Sufi begin by discussing the leverage ratio – ‘the ratio of total debt to total assets’ (p. 20). For the poorest homeowners, this ratio was near 80% and for the richest 20%, this ratio was only 7%. This is because the poor households borrow to purchase their assets (for example, a house). At the same time, the rich households deposit (credit) money with the banking sector to earn interest. The banking sector mediates the financial needs of the borrowers and the lenders. As Mian & Sufi write:

A poor man’s debt is a rich man’s asset. Since it is ultimately the rich who are lending to the poor through the financial system, as we move from poor home owners to rich home owners, debt declines and financial assets rise. (p. 20)

This observation immediately points to the need for looking at inequalities of income and wealth when studying debt or credit. Indeed, ‘[a] financial system that relies excessively on debt amplifies wealth inequality’ (p. 25). This is because when house prices fall, the decline in net worth for the indebted poor households will be more than proportional (p. 22-3).

       The authors rightly note that ‘the Great Recession was consumption-driven’ (p. 30) for ‘the decline in overall household spending in the third and fourth quarters of 2008 was unprecedented’ (p. 33). However, the dominant view in the US and across the world is what the authors term the ‘banking view’.

According to this view, the collapse of Lehman Brothers froze the credit system, preventing businesses from getting the loans they needed to continue operating. As a result, they were forced to cut investment and lay off workers. In this narrative, if we could have prevented Lehman Brothers from failing, our economy would have remained intact. (p. 31)

The dominant view locates the problem to be the lack of credit in the economy. And, they believe that if credit is made available at cheap rates (low rates of interest), the economy will revive. This view ignores the purpose of credit in an economy. Individual and firms demand money for consumption and investment (in a two-sector economy, aggregate demand is the sum of consumption and investment), and if aggregate demand falls so will the demand for credit. A fall in aggregate demand, as Keynes demonstrated in The General Theory, results in the reduction of activity and employment levels. This is precisely what happened during the Great Recession.

Job losses materialized because households stopped buying, not because businesses stopped investing. In fact, the evidence indicates that the decline in business investment was a reaction to the massive decline in household spending. If businesses saw no demand for their products, then of course they cut back on investment. (p. 34)

In other words, investment is not independent of consumption. This insight is of value in emerging economies like India where actual output is far below the potential output (large presence of disguised unemployment and underemployment), and political campaigns like ‘Make in India’ must be viewed with great caution. The dominant view is based on, what in growth theory is called, the supply-side growth theory. According to this theory, a growth in aggregate supply automatically generates an equivalent growth in aggregate demand. In House of Debt, the authors label this as the ‘fundamentals view’.

The basic idea behind the fundamentals view is that the total output, or GDP, of the economy is determined by its productive capacity: workers, capital, and the technology of firms. The economy is defined by what it can produce, not by what is demanded. Total production is limited only by natural barriers, like the rate at which our machines can convert various inputs into output, the number of working hours in a day per person, and the willingness of people to work versus relax. This is sometimes called the supply-side view because it emphasizes the productive capacity, or supply, of resources. (pp. 47-8)

That is, lower spending in the fundamentals view does not lead to contraction or job loss. Remember, output in the fundamentals view is determined by the productive capacity of the economy, not by demand. In response to a sharp decline in consumption, the economy in the fundamentals view has natural corrective forces that keep it operating at full capacity. These include lower interest rates and consumer prices … Obviously, however, these corrective forces weren’t able to keep the economy on track. (p. 49)

This view ignores the fundamental insight provided by Keynes in 1936. In a sense, the Say’s Law still lives on. And, in this theory, ‘[i]nvoluntary unemployment can only exist … if there are some “rigidities” that prevent wages from adjusting and workers from finding jobs’ (p. 56). These rigidities or frictions may be the following: presence of non-tradable jobs (that is, jobs which only cater to the local economy); wages do not fall; workers do not move; and the costs of reskilling if workers have to reallocate (p. 58, p. 63). For a critique and an alternative, see Thomas 2013.

       The marginal propensity to consume (MPC) varies across classes and therefore the assumption that everyone has the same MPC cannot be admitted. The MPC is high for poor households and low for rich households. ‘The larger the MPC, the more responsive the household is to the same change in wealth’ (p. 39; also p. 44). In fact, ‘the higher the leverage in the home, the more aggressively the household cuts back on spending when home values decline’ (p. 42). Therefore, debt matters. According to Mian & Sufi, ‘[t]he higher MPC out of housing wealth for highly levered households is one of the most important results from our research. It immediately implies that the distribution of wealth and debt matters’ (p. 42). Moreover, ‘[t]he MPC of households is also relevant for thinking about the effectiveness of government stimulus programs for boosting demand’ (p. 41).

       Very often, during recessions, the dominant policy response is the lowering of interest rates via monetary policy. But does the lowering of rates help? Is the problem a lack of availability of funds at cheap rates?

To help answer this, there is evidence from surveys by the National Federation of Independent Businesses (NFIB). Proponents of the bank- lending view are particularly concerned about credit to small businesses. Because small businesses rely heavily on banks for credit, they will be disproportionately affected. Large businesses, however, can rely on bonds or commercial paper markets for debt financing. The NFIB is informative because it surveys exactly the small businesses that should be most vulnerable to being cut off from bank lending. The survey asks small businesses to list their most important concern, where “poor sales,” “regulation and taxes,” and “financing and interest rates” are a few of the options. The fraction citing financing and interest rates as a main concern never rose above 5 percent throughout the financial crisis— in fact, the fraction actually went down from 2007 to 2009. It is difficult to reconcile this fact with the view that small businesses were desperate for bank financing. On the other hand, from 2007 to 2009, the fraction of small businesses citing poor sales as their top concern jumped from 10 percent to almost 35 percent. As indebted households cut back sharply on spending, businesses saw a sharp decline in sales. (p. 128)

As the survey indicated in the passage shows, the problem is a lack of aggregate demand, particularly consumption demand. ‘Companies laying off workers in these hard-hit counties were the largest businesses. This is more consistent with businesses responding to a lack of consumer demand rather than an inability to get a bank loan’ (p. 128). There is another issue here; this has to do with the effectiveness of the monetary policy mechanism. Hence, Mian & Sufi write: ‘[a]n increase in bank reserves leads to an increase in currency in circulation only if banks increase lending in response to the increase in reserves. If banks don’t lend more— or, equivalently, if borrowers don’t borrow more— an increase in bank reserves doesn’t affect money in circulation’ (p. 154) limiting the ‘effectiveness of monetary policy’ (p. 155). And there is no strict connection between interest rates and household spending; at the very least, a strong association cannot be assumed (see p. 161).

       This brings us to the end of this book review. It was noted in the introductory paragraph that this book is also about doing good economics. Mian & Sufi point to the need for have a good theory to make sense of the macroeconomic phenomena. This blog concludes with their view on the role of theory.

The ability to interpret data is especially important in macroeconomics. The aggregate U.S. economy is an unwieldy object – it contains millions of firms and households. … But unless an economist can put some structure on the data, he or she will drown in a deep ocean of numbers trying to answer these questions.

Which brings us to the importance of an economic model. Macroeconomists are defined in large part by the theoretical model they use to approach the data. A model provides the structure needed to see which data are most important, and to decide on the right course of action given the information that is available. (p. 47)

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