Wednesday, August 20, 2014

Housing, the Weakest Link

Let's run down the macroeconomic checklist. Inflation? It seems to be heading slowly back to the Fed's target of two percent. Unemployment? We're two quarters away from full employment, at least as the Congressional Budget Office defines it. Labor markets more generally? Also tightening, now quickly. Output? Steady overall.

Housing? If there is anything that looks worse than before interest rates jumped in summer 2013 -- that is, something that would suggest a reassessment of where monetary policy is headed -- it's housing. Everything else looks soon to be ready for monetary policy's exit.

One-unit residential construction had begun crawling upwards from historic lows in 2011 and 2012. Then comes the fear of the taper and -- wham -- the rebound in construction just stalls out.

It's no less apparent if you include multifamily housing. Real residential construction spending is also ugly. So it's no surprise that residential fixed investment as a share of GDP has been flat for the last four quarter at its super-low level. New one-family home sales are stalled out, too.

Why should all that be a subject of concern?

Keep in mind that for much of that trough, exceptionally weak housing was one of the main factors the Fed cited in its monetary-policy statements as cause for keeping its policy rate at zero. And it was the essential reason for why the Fed got involved on the longer end of the yield curve. "The housing sector continues to be depressed," or a similar phrase, sat in the top paragraph summarizing economic conditions for years. The current phrase is: "The recovery in the housing market remains slow." That seems a considerable overstatement of where we are. The recovery in the housing market is not slow. It's nonexistent. It has been since July 2013.

That suggests the housing sector is at the moment substantially more dependent on relaxed monetary conditions than I, and quite a lot of other analysts, thought it was when mortgage rates jumped. For a while since then, I have been worried about the apparent disconnect between prices and construction, as resurgent home values should push a lot of buyers into the market for newly-built homes. That wasn't happening. Now, however, the contradiction may be resolved in an adverse way: Home prices have stopped rising for the last few months.

There may be more to the weakness in housing than just the jump in interest rates. The U.S. is still amid the deleveraging process for mortgage debt. And, as John Carney and Justin Lahart write, it's hard to see why young people would be taking on new mortgage debt, what with their student loans and their at-best modest income prospects for now. Jed Kolko of Trulia makes the point even more convincingly with MSA-level data, showing that job growth has surpassed rebound effects as the main determinant of home-price appreciation. I have no doubt that all of these bigger forces are at play -- but look at the graph again. Does the housing recovery not stall out right in summer 2013?

Housing seems to provide a more unambiguous case for a slow exit than labor markets at this point, even if that's what the Fed has chosen to talk about at Jackson Hole this week. This rate of construction is not at all what the U.S. should be seeing if monetary easing can rightly declare mission accomplished.

Monday, August 18, 2014

Vacation Is All I Ever Wanted

Here I am in Vox, investigating the decline of the American vacation:
Nine million Americans took a week off in July 1976, the peak month each year for summer travel. Yet in July 2014, just seven million did. Keeping in mind that 60 million more Americans have jobs today than in 1976, that adds up to a huge decline in the share of workers taking vacations.

Some rough calculations show, in fact, that about 80 percent of workers once took an annual weeklong vacation — and now, just 56 percent do.
While I've got the dataset on hand, I figure I might as well figure out when Americans take weeklong vacations, by month. So, here you go.

Part of the reason these calculations are "rough," as I wrote, is that we're operating from the assumption that the reference week (which includes the 12th of the month, per Current Population Survey rules). It is obviously wrong to use the week that includes December 12 to estimate absences in December, because, you know, Christmas. But this is may well be cancelled out for similar, opposite phenomena in other months.

I've made my data available here for easy replication. And, in case you're wondering why I know that song reference in the title -- the year it came out minus my age is a negative number -- you may find it amusing to know that this was one of the classics of my childhood.

Sunday, August 17, 2014

Secular Stagnation, Meet Data

There is a new e-book out on secular stagnation, with contributions from Larry Summers, Barry Eichengreen, Paul Krugman, Olivier Blanchard, and others. It offers a lot to discuss, but I'm struck by something mostly missing: implied forward real interest rates.

This seems like it should be important data for the hypothesis, but it's only discussed briefly in the chapter by Frank Smets and two other economists. The graph, fittingly enough, is on the very last page of content.

If real interest rates are going to be low for a long period of time, as secular stagnation implies, then the market should say that, and the way it would is through forward rates. So what do we see?

The first graph shows the instantaneous forward real interest rate -- basically, what the market thinks the cost of overnight funding should be in real terms at some future date -- as derived from TIPS yields. There are more precise ways to do this, but it's close enough for a blog post.

Markets anticipate that real interest rates will return slowly to one percent. For reference, prior to the recession, these rates averaged about 1.5 percent, at least on an ex-post basis.

Another way to look at this is to figure out the implied real forwards for longer-term bonds. This builds in market views on what the term premium will be in the future, of course. The market's message is generally the same: Real interest rates will be the same as, or modestly lower than, where they have been in the past. Most of the depressed position of interest rates comes from the short run.

It's early to come to any solid conclusions about what the secular-stagnation discussion has and hasn't accomplished. Yet the thought that lingers for me is: Why do we need "secular stagnation"?

For all the interesting discussion so far, much of it in this book, nothing has yet convinced me that secular stagnation is a necessary and unique component to my understanding -- my mental model -- of the post-recession global economy. What someone who is convinced needs to do is identify the key facts that cannot be explained by deleveraging and the huge shock to nominal income.

The closest anyone has come, in fact, was Summers when he discussed the mid-2000s as a period of mediocre growth despite pedal-to-the-metal monetary policy. Krugman's "observation #2," that there seems to be a long-term trend towards ever-lower real interest rates, is also getting there. The bar, generally speaking, for a new theory to get into a model is that the model's predictions must be otherwise inconsistent with reality.

There just doesn't seem to be such a need for an additional "secular stagnation" component, as I interpret the data above. There is nothing outrageously low about forward real interest rates. If secular stagnation is merely an organizing device, the problem is that it seems to want to say something about the future, whereas the base case of deleveraging and the nominal-income shock speak mainly about the past. That's why the issue must be cast in light of forward interest rates -- and why I remain sympathetic but unconvinced.

Sunday, August 10, 2014

Ground Control to Major Tom

I am back. Posting will resume over the next month, after radio silence since May.

Also, an important disclosure: I am working on research for Professor Atif Mian for the remainder of the summer.

I have a longstanding personal rule that I try to minimize the amount I write about Princeton economists, because it invites concerns about my incentives from readers and needlessly complicates my relationships at school. This can't always be maintained -- for example, Paul Krugman called me out in a lecture one time this spring. But I try not to go out and write about stuff my professors are doing.

After interviewing Mian's co-author Amir Sufi back in May on their book, House of Debt, Sufi mentioned me to Mian, not at my prompting. Mian then reached out to me, offering me a research position, specifically at the Julis-Rabinowitz Center for Public Policy and Finance, which he runs. I accepted. Schoolwork comes first, and this is a great opportunity.

Saturday, May 3, 2014

Why Participation Is Down

There have been many attempts to answer this question: Is the decline in the U.S. labor force participation rate structural or cyclical? Or, more precisely, to what extent is it either one?

And there have been so many attempts because it really is an important question. Think about the economy as a big machine that takes three inputs -- technology, labor, and capital -- and produces output. The drop in the labor force means that the U.S. has forfeited, perhaps permanently, that labor input and whatever marginal output it would have yielded. A simple calculation1 suggests that the share of output lost is about three percent; more in-depth calculations from Reifschneider, Wascher, and Wilcox (2013) place it at the center of their estimate of a seven-percent drop in potential output. That's a lot. You don't blow three percent of GDP, let alone seven, every day.

Another reason that economists keep coming back to the labor force participation rate is that, ominously, it keeps falling. Not only does that render much of the research overtaken by events, but also the data presents a challenge to reports that see the decline as cyclical and transitory.

I'd also say that the reason that the research continues2 is because it hasn't settled on a single analytical framework. That's not necessarily a bad thing at all, as disagreement over methods forces researchers to reconcile differences in results rather than herd around a single conclusion. Yet to a certain degree it reflects dissatisfaction with the methods offered so far.

In this post I take an approach that is mostly3 new to the question of the decline in the labor force participation rate but will be familiar to most labor economists, the Blinder-Oaxaca decomposition of a probit model for the labor force participation decision. I use microdata from the March 2007 and 2013 supplements to the Current Population Survey, downloaded from IPUMS. I conclude that, of the 2.8-percentage-point decline in the labor force participation rate over that six-year period, more than half (1.7 percentage points) can be explained by underlying changes in demography, though a substantial fraction (1.1 percentage points) cannot.

The method

For the majority of my audience that has no idea what a Blinder-Oaxaca decomposition is, here's a quick 101. It's a statistical technique invented by Alan Blinder and Ronald Oaxaca in 1973 that takes the change in a variable and determines how much of it can be explained by a set of other variables in a model and how much can't. (Note: What comes next gets rather mathy, but you can skip down to "My idea..." if math isn't your thing.)

For example, Blinder and Oaxaca both wanted to understand why people differ in their earnings. Let's say that you think pay is determined by a bunch of factors, like your education, work experience, occupation, and so on. Let's put all of those factors into a matrix X, which contains data on lots of people. Let's put all of their earnings into another matrix Y. Then we can estimate the impact of all of those factors by an ordinary least squares regression:

Y = Ε

where β is the matrix of coefficients, which reflects the impacts of the factors, and Ε is a matrix of residuals

Now here's the innovation from Blinder and Oaxaca: If we want to understand a change in Y between two periods, then in the context of our model, there can only be two things going on. Either X or β could have changed -- that is, there could have been an underlying change in the determinants X of pay Y, or there could have been a change in the impacts of factors, reflected in β. We can express that idea as:

ΔY = Ya - Yb = (X- Xb)βb + Xa(β- βb)

where the "a" subscripts are for the "after" period and the "b" subscripts for the "before" period. You can think of the first term as the explained share, changes in the composition of the independent variables. And you can think of the second term as the unexplained share, changes in effects.

Now, my application of this model is a little bit more complex, because we're trying to explain a binary variable. "Are you in the labor force?" can get an answer of yes or no. So I've used something called a probit model, which allows us to estimate the probability that you answer yes or no to that question, given your characteristics. Our changes in the probabilities can also be divided in just the same way into changes in characteristics and changes in the effects of characteristics.

These techniques might seem exotic or advanced to newcomers. To economists, though, they're standard practice. So much so that it's surprising that I was not able to find a single piece of research that did what I think should be the first cut at answering this oh-so-important question about the decline in labor force participation. 

My idea, to be sure, was pretty simple. Here, I'll explain it without the math. Create a model that includes everything you think might be relevant to the decision of whether to participate in the labor force or not. Find data on an "after" period (March 2013) and a "before" period (March 2007). Then see what change in the labor force participation rate the model predicts. But, whatever you do, don't tell the model that a recession happened between 2007 and 2013. Include everything you think might explain the labor force participation decision in a structural capacity -- but nothing else.

My dataset is the March 2007 and 2013 supplements to the Current Population Survey. That gives me a sample size of roughly 150,000 people for both years. To predict whether or not each of these people are in the labor force, I had data on lots of different things: their age, sex, race, marital status, health status, disability status, education, whether they are currently enrolled in school, whether they're a war veteran, whether they have young children at home, and whether they're on welfare. 

It turns out that all this information is enough to make a good guess at whether you actually are in the labor force or not. On average, the model gets it right 81 percent of the time, assuming that you think of predictions of 50 percent and above as a "yes" and below 50 percent as a "no."

And I've deliberately gone out of my way to include common narratives about why the labor force participation rate has fallen. The aging and retirement of the Baby Boomers. The rise in worker disability. The rise in college enrollment. Furthermore, the unexplained share of this method will identify the specific areas of unexplained changes -- for instance, if women en masse suddenly have decided to stop working (and it turns out they haven't), this method will point at that issue. So one of the huge advantages to this approach is that it allows us to do a bunch of tests of specific theories one-by-one and say whether they hold water or not. 

The results

The headline result is that 1.7 percentage points of the decline in the labor force participation rate are explained by changes in the demographic composition of the population, and that 1.1 percentage points are left unexplained. The 95-percent confidence intervals on those figures are that between 1.4 and 1.9 percentage points are explained and between 0.8 and 1.4 percentage points are unexplained. 

This is a good place to note that I've made my .do files available here, so that you can go home and replicate this work, as I know you're all dying to do.

What matters to explaining the decline in the labor force participation rate? One thing above all else: aging, which explains 1.3 percentage points of the drop. The next most important: enrollment in school, which explains 0.8 percentage points of the drop. Remember that individual explanations can sum to more than the total, because there are other changes that partially offset. For example, the rise in educational attainment, which comes from this enrollment, explains a 0.6 percent rise in the labor force participation rate, because the well-educated work like crazy.

What matters less? The rise of disability, which explains 0.2 percentage points of the drop. The decline in the birthrate during the recession, which would suggest a 0.1-percentage-point increase, since fewer people are tied down at home with four-year-olds. 

And what just straight up doesn't matter? Changes in the share of people on welfare, disability aside. Changes in health, after accounting for disability and age. Changes in the sex and race composition of the labor force.

It also turns out that there's no single category that absorbs most of the unexplained share. In fact, the model puts almost all of the unexplained share into a constant. Which basically means that the model is saying, "Whatever your background, take what your probability of being in the labor force was in 2007 and mark it down by some amount for your 2013 probability." I found this compelling evidence that what our model says is unexplained really is the business cycle, and not some omitted structural explanation.

Here, also, is maybe a conclusion you wanted: What does the model predict the labor force participation rate is in March 2013 based on these changes in composition? 64.7 percent, as compared to an actual rate of 63.5 percent. Perhaps this makes you view my conclusion differently, if "less than half cyclical" sounded dour. This wouldn't be a trivial amount of recovery, as you can see in this graph. The black dot not on the line indicates the March 2013 counterfactual.


I've been meaning to write a post on this for a long time. It is the analytical challenge of our era for economists. It's taken me so long to put together an estimate because I wanted an approach I could defend.

One valuable side note is that the change in the working-age labor force participation rate is probably a good rule of thumb for the change in the overall structural labor force participation rate. The drop is about the same as predicted. Which makes sense: These are people whose labor force decision should not be sensitive to the business cycle. They're in the working period of their lives.

I should also mention some shortcomings of this analysis. One of them is that I've only used data from two months, the March 2007 and 2013 CPS supplements. This was mainly out of convenience, as that was the data available on IPUMS, the database I linked to earlier.

Another concern is the obvious endogeneity problem with education. That is, if the economy's terrible, that affects your decision of whether to work now or to go back to school. But note that this problem is insoluble without a model of how the economy affects education decisions, something well beyond the scope of my work here. What my work suggests, though, is that this exercise is worthwhile. Since you get a year older every year, there's not a lot of mystery to the aging-working link. But, since we know now that education decisions were actually important to driving down overall labor force participation, maybe we should go back and think about it carefully.

A final concern is that a lot of the prior research I looked at includes what are called "cohort effects," that is, you think about labor force participation evolving differently for different generations of people, based on their pre-recession starting age. I don't do that in this model. If cohorts matter, this approach will miss it.

Part of my hope of writing this post, whether or not you agree with the overall conclusion, is to enlighten people about the explanatory power of all the theories on the table. If you're on the right, and walk away from this post saying, "Gosh, I wasn't convinced that the decline in the labor force participation rate is partly cyclical, but wow, maybe it really isn't all about more people on welfare," I'll take that as a victory. Or, if you're on the left, and think, "Gosh, I wasn't convinced that the decline in the labor force participation rate is more than half structural, but wow, maybe aging is a bigger part of the story than I thought," I'll also take that as a victory. And, for sure, this won't be the last word. There are many other compelling approaches, each with their advantages and disadvantages. But I think this is an important one that needs to be added to the conversation.

If you have questions, I'm happy to answer them in the comments.


1. Assume that GDP is described by a Cobb-Douglas aggregate production function with a labor share of 0.6, consistent with U.S. levels. Then, holding capital and technology constant, you would predict that a 5-percent drop in the labor force participation rate would cause a 3-percent drop in output.

2: You can find a good literature review in Erceg and Levin (2003).

3: There is an exception, Hotchkiss and Rios-Avila (2013). But it does something I think is not good, which is that it includes a measure of labor-market conditions. My approach differs importantly in that I don't include one because I want to see the conclusions of the model without telling it about the recession. I have some other concerns about the particular measure they've chosen and whether we really can include it in the model if it is codetermined with labor force participation.

Update: I've made my fully cleaned up .dta file available for direct download here.


Further results:

Alan Reynolds of the Cato Institute asked me to try repeating the decomposition with broader measures of welfare programs -- the one I used originally was narrow, i.e. TANF, and Reynolds wanted SNAP (food stamps), Medicare, and Medicaid.

Following other ideas in the comments, I also included cubic and quartic terms in the age, so as to better approximate the curve of the LFPR in the cage. I found that inclusion of the extra age terms didn't do much.

I found that the increase in the fraction receiving public health insurance was an important explanatory variable for the decline of the labor force participation rate: It explains about 0.6 percentage points. I found the increase from SNAP was rather small: It explains 0.2 percentage points. In the new specification, fully 2.5 percentage points of the 2.8 percentage point from in the LFPR is explained by changes in the composition of the workforce.

I would strongly caution Alan, or anyone really, from interpreting this as a causal result. Don't conclude that because Obama expanded Medicaid and food stamps, those new recipients aren't working any more. I imagine that most of this growth was the result of the business cycle. The causal pathway probably goes from unemployment to those programs. I am aware Medicaid expanded permanently, but there is no way to disentangle this.

Tuesday, April 29, 2014

The Fishermen

Stephen Williamson and John Cochrane have raised a radical question: What if we have the sign wrong for monetary policy? What if low interest rates reduce inflation and high interest rates raise it, that is, rather than the other way around?

Their basic argument is this: If the real interest rate is fixed, then when the central bank raises the nominal interest rate, it also raises the inflation rate; when it lowers the nominal interest rate, it also lowers the inflation rate.

You can see that in the Fisher relation, which is:

i = (1+r)(1+π) ≈ r + π

where i is the nominal interest rate, r is the real interest rate, and π is the inflation rate. The time preferences of agents in the economy fix the real interest rate, and the central bank specifies policy in terms of the nominal rate. 

Noah Smith has a useful summary of the debate; he counts himself among the supporters of the "Neo-Fisherites." I think the term "Fishermen" is catchier. David Beckworth, who prodded me to write up some thoughts on this, argues that economists have conclusive historical evidence against the Fishermen. After World Wars I and II, governments pegged the interest rates on their debt very low; what they got was explosive inflation. Ryan Avent also points out that expectations are key here -- and should be in the Fisher relation I wrote above.

I think there are basically two problems with the debate. The first is that the Fishermen wrap a dubious claim in an identity and a modeling assumption. The second, which follows from the first, is that if this debate is about anything, it's not really about the Fisher relation at all. It's about the wrapped-up claim.

Look back to the Fisher relation, and you'll see that it's true by the construction of the model that when the central bank raises the nominal interest rate, the inflation rate must rise. That's an identity, and we've said that the real interest rate is fixed.

But the problem with this argument, which looks airtight, is that it misconstrues what the Fisher relation is. What it really says is when the central bank raises the nominal interest rate, the inflation rate consistent with a steady-state equilibrium also rises.

Note that what I've done here is add in the words "consistent with a steady state equilibrium." This isn't mere semantics. It matters because the central bank's power in one sense is materially weaker: It no longer picks the current rate of inflation off a menu, but rather only the rate of inflation that can be sustained. Yet it also means that the central bank's power is, in another sense, materially stronger: It can distort the real interest rate in the short run.

Why does this matter? Because what I've shown is that wrapped inside Williamson's and Cochrane's point about the Fisher relation, which is just plain true, is an actual claim, and a dubious one: After the central bank raises the nominal interest rate, and thereby the steady-state rate of inflation, inflation will actually rise to that steady state. Cochrane embeds this assumption to the model if you look carefully; Williamson doesn't seem to discuss it.

So the first point is that the Fishermen aren't wrong. In fact, they can't be wrong. They're wrong about what their conclusion is. The second point is that the Fisher relation is in fact tangential to the whole debate. If Williamson and Cochrane are arguing anything at all, what they're arguing is the point about dynamics -- i.e. that inflation is well-behaved and goes to the new, higher steady state the central bank chooses when it picks the higher nominal interest rate.

Does the inflation rate explode when it starts out above the central bank's choice of equilibrium? Or does it converge nicely to the equilibrium? Do we fall into catastrophic deflation when inflation starts out above the central bank's choice of equilibrium? Or can we actually raise inflation by hiking rates? And, even if the dynamics aren't explosive, the interest-rate peg still means that the price level can float anywhere, depending on the sequence of shocks.

In case it's not totally obvious, I think we're in the second world. That's a view informed by a longstanding theoretical tradition in macroeconomics that the price level is indeterminate when the central bank pegs an interest rate. That's exactly what the second picture shows: If you don't start out at 2, then the dynamics get completely out of control.

It's also a view informed by data. Beckworth beat me to the punch when he looked at historical episodes of interest rate pegs and saw exactly what Sargent and Wallace predicted. I would also point out that we have really strong evidence, also from Sargent, that the way to stop hyperinflation is to hike interest rates hard. That would be literally the worst thing you could do if you cast your line with the Fishermen.

More: Via Tony Yates, I am reading Cochrane (2011), which gets into many of these issues. Also, I just noticed this new working paper from Williamson, which, interestingly, also digs into the indeterminacy problem. If you look on page 12, his argument about the Fisher relation pops up. Update: I got rid of the illustration because Noah found it confusing.