Well, This is Embarrassing

Harvard economics chair Greg Mankiw has decided to repeat incorrect right-wing talking points that defy common sense. Yesterday he posted (and this is the entire post, not an excerpt):

John Lott points out the following: “So far this year there have been 848,000 new jobs. Of those, 813,000 are part time jobs…. To put it differently, an incredible 96% of the jobs added this year were part-time jobs.”

That’s astonishingly bad. It’s also very incorrect. From the perspective of being misleading, perhaps most important is the failure to distinguish between part-time jobs worked for economic reasons (which the Bureau of Labor Statistics (BLS) defines as: slack work or business conditions, could only find part-time work, seasonal work, job started or ended during week) and non-economic reasons (defined as child care, family obligations, health problems, being a student, and a few others). Looking at Lott’s own data, since January, there are 62,000 fewer part-time workers who are stuck in part-time jobs for economic reasons. The growth in part-time jobs has taken place entirely for non-economic reasons.

Even setting aside the distinction between voluntary (non-economic) and involuntary (economic) part-time work, Lott still has two big methodogical problems. First, the time-frame he uses is not nuetral, and second Lott combines the data series in a way that BLS did not intend. To be fair, Lott does update his post to note that using correct BLS data, just under 2/3rds of new jobs from Jan 2013-Aug 2013 are part-time. This is still really high, but not the eye-popping 96% he initially claims and Mankiw repeats. But it also turns out that the first eight months of the year aren’t really a neutral time-frame, as January was a low-point for part-time workers. Going the full year from August 2012-August 2013 I find 1.716 million more full-time jobs and 288,000 additional part-time jobs. That makes part-time jobs 14.4% of new jobs over the last year. Now, if there’s a reason to think that the overall economy changed drastically in January then there’d be a case for throwing out the August-August comparison in favor of the shorter time frame. But I don’t see one. Using the same Bureau of Labor Statistics data that Lott is, here’s a graph of last year’s part-time and full-time jobs:

Part Time and Full Time Jobs

The big trend that sticks out is that they’re both flat. The economy is not doing well. But part-time jobs aren’t exactly surging. They did during the recession, and it is a problem that they haven’t come back down. Here’s a longer view of part-time jobs as a percentage of total jobs from the Federal Reserve (note: you want to look at the red line that adjust the data for a change in CPS surveying methods made in 1994):

FED part-time employment

Again, a huge spike during the recession, but not in 2013. The point here is not to try to paint a rosy picture of the economy. The point is that an economics professor at Harvard ought to know enough not to repeat statistics that seem too extreme to be credible, and come from a disreputable source, without first doing a little checking on his own.


7 thoughts on “Well, This is Embarrassing

  1. We probably won’t get a full picture of what’s going on with part time workers for a few more months, but it does indeed look like there’s something going on in the labor market.

    I’m not sure it’s embarrassing for Mankiw to link to Lott’s post on the same day. To Lott’s credit he has updated his initial post several times.

    • The link in your post does not work. Can you re-post the url? I do not think it’s embarrassing or even wrong to argue that part-time employment is making up a large chunk of the very small jobs recovery. But to re-post a stat claiming 96% of net job creation in the past year is part-time while ignoring broader trends and implying that this is the result of a weak economy (by ignoring the difference between economic and non-economic part-time job growth) does seem, to me, to be a somewhat embarrassing lack of basic analysis by an economist.

      I, like most people, would like to have a clearer picture of the economy. Mankiw’s post did not help. (Well, I suppose the motivation to go look at a few of the numbers on my own could be construed as helpful to me personally, but for the people who just read his blog I consider his post to be clearly misleading).

  2. 1) Who ignored the difference between economic and non-economic part-time job growth?
    2) Why do you say that there is “correct BLS data”? You don’t acknowledge or let alone address my discussion of the what I did (adding together the seasonally adjusted economic and non-economic part-time job growth or adding together economic and non-economic part-time job growth and then do the seasonal adjustment). Please explain why one set of data is obviously correct. I am disappointed that you ignored my discussion of this issue and just assert that one measure is correct.
    3) Where is the fraud in what I did? As usual, I show all the data that I have used (I put up screen shots and acknowledged the difference between economic and non-economic part-time job growth) and I provided the links in case someone wanted to look at the data more or who were unfamiliar with what the data was actually measuring. When a debate ensued, I updated my post with the new claims and my responses. If you have read my book More Guns, Less Crime, you will know that I regularly quote at length from my critics. And for someone who is attacking others for accuracy, if you think that the Washington Monthly discussion (or its sources such as Media Matters) is useful, it doesn’t appear that one is showing the same level of accuracy that you say you are requiring of others. For example,

    • 1) Greg Mankiw. While the distinction is presented in your data it is ignored in your conclusion, and hence ignored by Mankiw.
      2) I am unsure why the BLS data does not seem internally consistent. But it is clear that using the data you originally use and using the BLS data pointed to by the department of numbers yields very different outcomes. Given the need to choose one, I opt for the one put together by the BLS and recommended by others more familiar with BLS practices instead of one put together based on different BLS series.
      3) I do not think there is any. Indeed, I am pleased with the amount of data you show and the number of times you updated your post in response to criticism. While I maintain disagreement, and would like to see the data presented in a multi-year context, I have no real problem with your post. I do have a problem with others, particularly prominent economists, citing your conclusion in a way that implies that a poor economy lead to an explosion of part-time jobs in 2013, without doing a little more digging into the data themselves.

      • Thanks.
        1) My post notes “(It isn’t clear to me why we see the differences in part time for economic and noneconomic reasons.)” Given that Mankiw links to this, I am not sure where any problem arises. Possibly more importantly, the very first data presented right at the top of the post is for the part-time for economic reasons and thus it would be hard for people to miss the difference.
        2) There is a big difference between saying that you personally want to opt for one data series over the other and you saying that one data series is “correct.” Since all the data here is “put together by the BLS” and the sum of the two components adds up to the total, I don’t see how one can infer that one data series is recommended over the other. My guess is that if you were to ask the BLS economists which series they recommend, they would probably tell you that there is no way to determine which is “right.”
        Given that all that, I assume most would argue that the “true” number is likely to be in between 63% and 96%. With you already conceding that 63% is a high number if not as amazing as 96%, there is a real question about what is happening this year and I have tried to indicate that in the series of questions that I ask. To me the most striking evidence is the figures that I have added in an update. Doing this over early periods has a correlation that is about 30% of what is true so far during 2013.
        3) Thanks, but I don’t see any problem with Mankiw or others referencing what I wrote, particularly as they are just quoting a couple sentences, adding ellipses so that people know that there is other material, and linking to my original post.

        Finally, let me review the first sentence in your post. “Harvard economics chair Greg Mankiw has decided to repeat incorrect right-wing talking points that defy common sense.” a) He is not repeating “incorrect” information. b) My blog just pointing to what I trust we all agree is a puzzling relationship. If you want to call them “right-wing talking points,” that is surely your call, but even you seem to concede that there is a real question here and I was honestly trying to point to what I thought was a striking set of numbers. c) Again, even you seem to concede (whether the true number is 63%, 96%, or something in between) that there is a real question here so I am not sure how you can claim that it defies “common sense.” My suggestion is that you think about rephrasing your headline and at least your first sentence in a more respectful way appropriate for an academic debate on these issues.

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