How plausible is the zero marginal product of workers hypothesis?

In a not so recent post Tyler Cowen made the following argument:

Matt Yglesias suggests the notion is implausible, but I am surprised to read those words.  Keep in mind, we have had a recovery in output, but not in employment.  That means a smaller number of laborers are working, but we are producing as much as before.  As a simple first cut, how should we measure the marginal product of those now laid-off workers?  I would start with the number zero.  If a restored level of output wouldn’t count as evidence for the zero marginal product hypothesis, what would?  If I ran a business, fired ten people, and output didn’t go down, might I start by asking whether those people produced anything useful?

It is true that the ceteris are not paribus,  But the observed changes if anything favor the hypothesis of zero marginal product. There has been no major technological breakthrough in the meantime.  If anything, there has been bad monetary policy and a dose of regulatory uncertainty.  And yet again we can produce just as much without those workers.  Think of “labor hoarding” yet without…the hoarding.

I don’t normally comment on old posts, but I was asked what I thought of this idea, which still seems to be attracting attention.  My initial reaction is skepticism. Why wouldn’t companies just lay off more workers?  But Tyler Cowen refers to the labor hoarding hypothesis, which might be able to explain that seemingly irrational behavior.

So I think we need see how the theory matches the data.  This post by Stephen Gordon shows US employment in 2010:3 falling about 5% below its 2008:1 peak, while output seems to have declined only about 0.7%.  This is what Cowen finds puzzling. 

But I don’t see any puzzle at all.  If employment didn’t change, I’d expect US output to grow at about 2% a year, which is the trend rate of productivity growth.  Because we are looking at a two and a half year period, you’d expect output to grow roughly 5% with stable employment.  Now assume that employment actually fell 5%.  If the workers who lost jobs were similar to those who remained employed, I’d expect output to be flat over that 2.5 year period.  Because output fell slightly, it seems like the workers who lost jobs were slightly more productive than those who remain employed.

Do I believe this?  No, for several reasons I think they were less skilled than those who remained employed.  Labor productivity growth (assuming we were at full employment) probably slowed in the most recent 2.5 years, as investment in new capital declined.  Measured productivity continued to rise briskly, partly because technological progress continues in good times and bad, and partly because those workers still employed are somewhat higher skilled, or perhaps are trying harder in fear of losing their own jobs.  So Tyler is probably right that those workers who lost their jobs have a lower than average marginal product.  I just don’t see why zero is the natural starting point for consideration of the issue, as you only get that number by making some fairly extreme assumptions about technological progress coming to a screeching halt after 2008:1.

I’m certainly open to alternative views here.  My baseline assumption is not consistent with Okun’s Law, for instance.  And the three most recent recessions have seen slower recovery in employment than earlier recessions, although I think people often underestimate how much of that difference is because monetary stimulus has been much weaker during those recoveries (compared to a recession like 1981-82.)


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36 Responses to “How plausible is the zero marginal product of workers hypothesis?”

  1. Gravatar of cassander cassander
    14. January 2011 at 12:50

    Except we can all easily think of ZMP workers. For example, all HR departments. Which is not to say that HR is useless, but they can definitely be gotten rid of without affecting productivity in the short run.

    >Why wouldn’t companies just lay off more workers?

    People hate firing people. They do it as little as possible.

    >Labor productivity growth (assuming we were at full employment) probably slowed in the most recent 2.5 years, as investment in new capital declined.

    An economist’s fallacy! Labor productivity has as much to do with institutional capital as with traditional capital. During boom times, corporations expand, take on new roles, launch new projects, etc. Some of these will be more productive than others, and when the crunch comes the least productive and most labor intensive will be cut first, raising average productivity. The crunch also forces companies to search for economies, reorganize, and try to do more with less, which should also increase productivity.

  2. Gravatar of Benjamin Cole Benjamin Cole
    14. January 2011 at 13:03

    Excellent post–also, if memory serves, output per worker can surge in robust recoveries, as overhead gets spread over a larger number. One could (erroneously) conclude that rising productivity meant that marginal workers were better trained, worked harder etc.
    You also have to wonder if the data we work with is close enough to the actual economy to draw certain conclusions.

    A good question, worth pursuing for an academic-blogger type, is can unit labor costs keep going down, as they have been?

    It could be a recovery will spread labor costs over a greater number of units, while wages remain soft. I suspect we have another year of declining unit labor costs.

    That means Jimmy Hoffa will show up for my scheduled lunch with him before we see inflation.

  3. Gravatar of Indy Indy
    14. January 2011 at 13:10

    A related post on a different kind of ZMP worker – the Draft- horses of England, a century ago:

    “There was always a wage at which all these horses could have remained employed. But that wage was so low that it did not pay for their feed.”

  4. Gravatar of Morgan Warstler Morgan Warstler
    14. January 2011 at 13:18

    I think it is impossible to discuss this without discussing primarily Minimum Wage, and any other added per-employee costs. This includes the lost spending on time saving labor in the service class (cheap house cleaning), as well as needles loss of outsourced jobs (India call centers).

    http://biggovernment.com/mwarstler/2011/01/04/guaranteed-income-the-christian-solution-to-our-economy/

    I don’t think my argument above is trite, there is NO reason we have any unemployed at all.

    And for what we are spending in UI and various other aid programs, we could have near perfect employment.

    We could also instantly kill off 50% of the fed’s mandate.

    Benji, we’ll see inflation the moment you stop counting rents.

  5. Gravatar of Morgan Warstler Morgan Warstler
    14. January 2011 at 13:18

    I think it is impossible to discuss this without discussing primarily Minimum Wage, and any other added per-employee costs. This includes the lost spending on time saving labor in the service class (cheap house cleaning), as well as needles loss of outsourced jobs (India call centers).

    http://biggovernment.com/mwarstler/2011/01/04/guaranteed-income-the-christian-solution-to-our-economy/

    I don’t think my argument above is trite, there is NO reason we have any unemployed at all.

    And for what we are spending in UI and various other aid programs, we could have near perfect employment.

    We could also instantly kill off 50% of the fed’s mandate.

    Benji, we’ll see inflation the moment you stop counting rents.

  6. Gravatar of Jeff Singer Jeff Singer
    14. January 2011 at 13:33

    Scott,

    Do you have a regular email address folks can use to send you articles and such? I ask because I’m stuck posting a comment here where it doesn’t belong and I apologize for that!

    Anyway, for a guy like me who comes here to learn as much as I can about current monetary policy (it’s been awhile since I took my Macro econ courses as an undergrad and even then I probably didn’t learn the state of the art in theory as you present it here), I’m always interested in how you respond to critics. Specifically, there are a lot of Austrian/libertarian types who are as skeptical of monetary policy as they are of fiscal policy. For example, how do you answer this guy’s argument about the Fed taking on too much debt for the impact it’s having on unemployment:

    http://globaleconomicanalysis.blogspot.com/2011/01/hallucinations-on-curing-unemployment.html

    Love to get your thoughts on his post and on the broader topic of the Austrians.

  7. Gravatar of Kevin Dick Kevin Dick
    14. January 2011 at 13:50

    I’ve actually been working on formalizing the idea of institutional capital. The upshot is that a large fraction of employees are dedicated to improving existing production processes and searching for new opportunities. I call this “searching Production Function Space.”

    This has a lot of interesting implications. Not the least of which is that employees not directly involved in production are a very specific asset. So firms have a lot of short-run slack in hiring and firing as well as the incentive to make sure they don’t do either precipitously.

    My next post is actually planning on addressing these issues in detail. Previous posts are:

    http://emergentfool.com/2011/01/13/startups-small-businesses-and-large-companies/

    http://emergentfool.com/2011/01/09/thoughts-on-the-theory-of-the-firm/

  8. Gravatar of dtoh dtoh
    14. January 2011 at 14:58

    This is another one of these anybody who has ever managed a business immediately knows the answer type of questions.

    Economy goes south, first thing firms cut back on is activities (and personnel) which are non-essential to short term sales, e.g. R&D, marketing, customer support, etc. This will impact your sales (i.e. output) over the long term, but has minimal impact on short term sales (output). Ergo ZMP or near-ZMP over the short term.

  9. Gravatar of scott sumner scott sumner
    14. January 2011 at 15:48

    cassander, I’m not quite sure who your comment is aimed at, me or Cowen? I never mentioned institutional capital, and don’t really know enough about it to comment.

    Benjamin, Yes, I think unit costs will stay low.

    Indy, That’s “below feed MP.”

    Jeff, You should feel free to link to interesting articles in any comment section. I can be emailed at Bentley, but I prefer comments in the blog. He’s right that the 3 million figure is pulled out of thin air, but wrong about QE2 not working at all. And the “cost” of $600,000+ per job is a meaningless number, because it’s not a cost in the usual sense, it costs the Fed almost nothing to swap reserves for cash.

    Thanks Kevin, It seems like the first comment was addressed more at your posts than mine.

    dtoh, But the data I presented suggests that view is wrong.

  10. Gravatar of Kevin Dick Kevin Dick
    14. January 2011 at 17:47

    I thought so too, which is why I chimed in. I haven’t worked out the macro implications of my hypothesis yet, put if you’ve got a lot of specificity of employee skills in indirect production, you’d expect to see a whole lot of weirdness in how firms respond to fluctuations in demand. But maybe it all averages out.

  11. Gravatar of cassander cassander
    14. January 2011 at 18:45

    Sorry to be unclear. I was basically trying to say what dtoh said.

  12. Gravatar of Lorenzo from Oz Lorenzo from Oz
    14. January 2011 at 19:48

    Labour hoarding makes sense if you are worried about firm-specific skills. But that would surely affect which workers one hoards, not all workers and not all workers to the same amount.

    Labour hoarding also makes sense if there are major risks in hiring new people. This is true in highly regulated labour markets where the regulations protect incumbents (i.e. Europe). But then you would see low long-term employment growth and highly segmented labour markets (i.e. Europe: hence the US gets a big surge in unemployment and Europe gets riots).

    It seems that what one sees in the US is not labour hoarding, but one does see it in Europe. But if folk have zero marginal product, why were more than one per firm being employed in the first place? Surely it is a trade-off between current cash flow and future income expectations: or between short-term and long-term product as stated in comments. So, in the US, employment is cut and production marches along while, in Europe, employment is cut less and production is cut more.

  13. Gravatar of Dirk Dirk
    15. January 2011 at 00:54

    Thanks for that. A lot of us Marginal Revolution readers are just economics hobbyists trying to make some sense of the memes in the air. Or at least that’s my case.

    I updated my post on the subject, though I barely know what I’m talking about. I just sensed TC was off on this one.

    David Beckworth requested I create some scatter plots, so I did. Perhaps it is no news to economists, but I was fascinated by how increasingly “orderly” the scatter plots became as I plotted the stock-market against 3 Qtrs lag of the unemployment rate:

    http://dorsetnaga.wordpress.com/2011/01/14/zero-mp-workers-no-its-not-different-this-time/

    Anyway, great post and I’m hoping you put an end to this meme.

  14. Gravatar of marcus nunes marcus nunes
    15. January 2011 at 05:45

    Scott: Tyler Cowen weighs in:
    http://www.marginalrevolution.com/marginalrevolution/2011/01/when-will-people-move-away-from-pure-ad-theories-of-unemployment.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+marginalrevolution%2FhCQh+%28Marginal+Revolution%29
    I enjoy “mind boggling” people over here with the (slightly exagerated)statement: Over 4 or 5 quarters between 2008 and 09 the US shed a whole brazilian economy (which is the 8th or 9th largest)! What would that do to employment?

  15. Gravatar of bill woolsey bill woolsey
    15. January 2011 at 07:53

    Zero marginal product workers…

    And all of this is about some kind of myopic micro (and not real micro.)

    We live in a world of scarcity.

    Labor is scarce.

    It is possible that we live in a world of scarcity, but labor isn’t scarce. But that requires that the resources that go with labor are scarce.

    In other words, we can’t put the carpenters to work flipping burgers, because we don’t have the oil to make electricity, to run the stoves.

    The value of the additional burgers doesn’t cover the opportunity cost of the energy, or just covers it, so there is nothing to compensate the workers with.

    They have zero marginal productivity.

    The notion the we figure out how to produce a given level of output of some type with less labor, and that means that the workers that we don’t need to produce that given amount of labor have zero marginal productivity is absurdly wrong.

    If we can produce the same output with 10 percent less labor, then produce 10 percent more output.

    But we can’t sell 10 percent more output? OK. But that doesn’t mean the workers have zero marginal productivity. It means, of the face of it, there is an demand problem. Demand needs to be 10 percent higher.

    And, the marginal utility of that extra output is a bit lower, presumably. It is worth less. And so the marginal value productivity of the labor would be lower. But not zero.

    Thinking of one area in an economy, this lower marginal value product of labor implies that other things should be produced. (like the carpenters flipping burgers now.)

    And maybe they need new stoves, so we need to have people produce stoves.

    we are down to assuming that “land” is in fixed supply, and there isn’t enough to go with the labor.

    This zero marginal “value” product of labor argument assumes that the maringal utility of additional output is zero. No scarcity.

    How about this..

    The assumption appears to be that we have had a negative productivity shock, so output has gone down, but we have had a positive productivity shock, so we can produce output with less labor.

    Contradiction.

    Intead, just consider a decrease in the supply of energy. A factor complementary to labor. Ouput falls as does the demand for labor. If it were bad enough, the marginal value produce of labor could fall to zero.

    But output goes up and we don’t need as much labor would have nothing to do with it. It would be that high energy prices are raising costs and contraining output.

  16. Gravatar of StatsGuy StatsGuy
    15. January 2011 at 08:39

    First: The notion of zero marginal product of labor is ludicrous. Anyone who’s actually held a real job knows that the marginal product is often negative.

    Second, I take Kling’s side here, to a point. Bill W. writes:

    “If we can produce the same output with 10 percent less labor, then produce 10 percent more output. But we can’t sell 10 percent more output? OK. But that doesn’t mean the workers have zero marginal productivity. It means, of the face of it, there is an demand problem.”

    10% more of what? Conventional macro misses a few major dynamics in the real world that create problems for walrasian equillibrium. Here are a couple that directly impact the conversation:

    1) Employing labor is costly – you need to tell labor what to do. You need to train it, and keep it trained. You need to manage and discipline it. You need to pay accountants to cover payment, report tax info, etc. Even if wages are ZERO, labor is not free. Otherwise, you would not see college kids _competing_ for internships.

    2) In many places, where the marginal productivity is still positive, it’s still lower than the cost of labor unit survival in the existing social context. This is Marx’s argument. Here’s a simple example: there’s demand in NYC for maids at 10 dollars an hour (good luck!), but the cost of living in NYC is prohibitive. The cost of transit from outlying districts also prohibitive. The cost of security to prevent theft, etc.

    3) Even in simple cases, the marginal productivity of labor can be negative. Imagine workers tripping on each other in a burger flipping joint. Imagine a farm which ships berries to a processing plant. The plant has a throughput. You hire more workers in the field, which is great – you clear the field in a few hours instead of a few weeks. But then, the berries all melt in the hot summer sun waiting to be canned or frozen. You could build more plant, but the plant has maintenance costs (including non-labor costs, like materials and energy, which have negative externalities). In complex cases – like software – there’s a common maxim that adding people to a late project makes it later.

    You can, if you wish, think of this as transactional costs, or transportation costs in a sense – moving and organizing people and information is costly. But it’s also externalities.

    4) Macro presumes that demand CAN be infinite for the set of goods that is technologically feasible given production constraints. Demand, in a higher sense, is of course infinite – more health, more life, more prestige, more pleasure. But that doesn’t always mean more food (even though the US agri industry has been trying to increase consumption rates), it often means better food. For the existing infrastructure, marginal VALUE of consumed goods can be negative. Making more drugs is easy, better drugs is hard, and to be honest, the vast majority of people are not capable of contributing to medical research.

    So it’s easy to agree with Kling that the economy had structural problems in 2007/2008. Of course, a dynamic economy ALWAYS has structural problems, by definition. The question is RELATIVE magnitude, AND whether the optimal path to fix structural problems is wage compression or price/nominal gdp trajectory stability.

    But that does not do away with all of Kling’s argument, or the inevitable nasty conclusion that results:

    The world, and most people in it, would probably be materially better off if a lot of the people that are currently unemployed and unemployable simply vanished. Where, in macro, do we deal with people who are psychologically unstable and disruptive at work? Do we just count them as a smaller unit of labor, or a negative unit of labor?

    Econ was called the immoral science for a reason.

  17. Gravatar of jean jean
    15. January 2011 at 09:07

    Krugman officially reads your blog (though it was quite obvious he was reading your blog).
    http://krugman.blogs.nytimes.com/2011/01/15/zirp-and-zmp/
    He also mentioned NGDP targeting:
    http://krugman.blogs.nytimes.com/2011/01/14/monetary-morality/
    And also, Happy New Year!

  18. Gravatar of scott sumner scott sumner
    15. January 2011 at 14:20

    Kevin, My sense is that a lot of the weirdness does average out.

    Cassander. I find that when I make empirical arguments, people often ignore the data and just tell me what seems plausible based on what they know about the real world. Sometimes that works and sometimes it doesn’t.

    Lorenzo, I agree that there is much more labor hoarding in Europe than the US.

    Dirk, Yes, I agree that stocks are correlated with employment. Stocks are a key transmission mechanism for monetary policy.

    Marcus. Do you mean the fall in GDP here relative to trend was the size of the Brazilian economy?

    Bill and Statsguy, You are both thinking about the plausibility of the argument, and coming at it from different directions. My point is that it doesn’t fit the data. Employment has fallen 5% and the tiny fall in RGDP is what you’d expect for that employment decline if labor had a high MP and productivity was growing at 2% per year.

    Statsguy, I agree with Kling that the economy had structural problems in 2007. Of course unemployment was quite low, which tells me structural problems don’t cause recessions (normally.)

  19. Gravatar of scott sumner scott sumner
    15. January 2011 at 14:22

    Jean, Thanks, I have a post that mentions this.

  20. Gravatar of marcus nunes marcus nunes
    15. January 2011 at 14:36

    Scott: Yes, just about (relative to the original trend)!!!

  21. Gravatar of marcus nunes marcus nunes
    15. January 2011 at 14:37

    Scott: Yes, just about (relative to the original NGDP trend)!!!

  22. Gravatar of scott sumner scott sumner
    16. January 2011 at 18:42

    Marcus, That reflects poorly on both countries, given Brazil has more than 1/2 our population. (I suppose PPP GDP would look better for Brazil.)

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  25. Gravatar of Bryan Willman Bryan Willman
    17. January 2011 at 18:30

    I’d like to suggest that Human Limitations in management, and ability to consume, are part of the issue.

    Management – In the real world, management has finite time, energy, and skills. So it does NOT cruise along consistently firing losers and canceling useless projects. Rather, it waits until forced too, OR, waits until external circumstances make it easier. We must always remember that a great deal of management “mind share” is devoted to managing various kinds of liability, and being sued in various ways for firing somebody is one of these. Laying off a clump of people due to “business conditions” automatically provides a kind of political and legal cover.

    Ability to Consume – any one person has finite time, and a finite ability to imagine uses for any particular good or service. So raising output of some thing, and reducing price to be very low, will not raise consumption forever – at some point people just won’t want any more, or will be unable to employ more. Saturation (much studied in the computer industry) rears its ugly head.

    Historically, people have been more than able to consume all that the world and economy provided – but we *may* be coming to a time where that is not true anymore.

  26. Gravatar of scott sumner scott sumner
    18. January 2011 at 15:33

    Bryan, We are no where near the limit of what people would like to consume, nor the limit of what the planet can support.

    I agree about managers, but I think it’s a minor factor in the recession.

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  28. Gravatar of Bryan Willman Bryan Willman
    20. January 2011 at 22:14

    Scott – I am sure we are nowhere near what people would like to consume, but do they really have time (one very hard resource limit) to consume all they would like?

    It is already the case that I cannot read fast enough to read every blog or webpage that I *ought to*, let alone books. And somebody who (unlike me) has a full time day job (work or childcare or whatever) would have even less time. So, for example, making all books free may not increase readership on the whole very much.

    Likewise, obesity is on the rise, even among the not-at-all-well-off (sometimes worse among them) – so many of us cannot afford to eat any more *because it is bad for our health*.

    Of course, there are very very few people who couldn’t consume more/better housing, education, and so on.

    (I do agree that “the planet” is just fine and probably so are most of its ecosystems, various societies and sub-societies are profoundly screwed up, but that’s a different issue.)

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  31. Gravatar of scott sumner scott sumner
    22. January 2011 at 07:14

    Bryan, Most people would like a Rolls Royce, a a mansion and servants

  32. Gravatar of Alan Alan
    13. April 2011 at 14:18

    Scott, I do not usually comment on old posts either, but please tell me where I go wrong in the reasoning below:

    The ZMP discussion seems to me to flirt with the edges of the fallacy of misplaced concreteness (N. Georgescu-Roegen, A. N. Whitehead). MPL is not a characterization of the last employee hired *only*, in part because the capital employed forms a constaint and people “step on each other’s toes.” (see, e.g., http://en.wikipedia.org/wiki/Marginal_product_of_labor#cite_note-Perloff176-5). This is indicated explicitly by Samuelson in his economics textbook, *Foundations of Economic Analysis*, Harvard, 1947:

    “[I]t is important to underline that the marginal product is not, properly speaking, the econtribution of the marginal unit *by itself*. Some commentators (e.g, E. v. Bohm-Bawerk) seem to have gone on to make arguments that seem to imply [that the new worker added to the enterprise produces exactly the amount reflected in the marginal product]. Of course this is not necessarily true. The second man may very well produce more or less and still the total output increases [because the second man reduces his output correspondingly]. [B]y *adding* the second man, output was increased by [say] *eight*. *Thus*, the marginal product of the second man is eight. But his actIual contribution may be very different than this.” [all emph. in original]

    Therefore to say that *the worker has a MP of zero* seems inaccurate. Labor for the economic process taking place in a particular enterprise exhibits MP of zero, not the laborer. *It is a characteristic of the production function*, not of the worker. The question “whether those people produced anything useful” seems therefore, in the Neoclassical paradigm, without import.

    Let’s assume “we are indeed producing as much as before” and that the metric for this is reliable, apples-to-apples, etc. The workers that are let go may have brought about the situation that the firm’s production function exhibit ZMP in the industry in which they worked (because of the constraints there). It only seems that, yes, the marginal/last/final hire will have the least productivity that would “cause” the total output increase to become zero, but it does not follow that he would *possess* the least skills or is loafing—this is not just a skill problem. MPL is specific to the industry/firm/economy just as well as to the skill level (at least in the short run). Furthermore, ask any HR department and it will become apparent very quickly that the people usually let go are not the ones with least skills—last in first out regardless of skill, disguised as most-recent-non-performance, wins out most of the time.

    Now,

    Marginal Revenue Product of Labor -> MRPL = MR x MPL or 0 or even =0, the specific case of contention) *at existing employment level’s MPL*.

    People become analogous to the horses Indy mentions *only if* the equilibrium wage, w = MPL < s, where s is the subsistence wage. Note that this may happen even if the demand curve for labor (determined by MPL) crosses the labor supply curve *but below s*–the income allocation issue becomes thorny and “Malthusian” at that point *if* the allocation method also tries to use the assumption of strict hedonism and profit maximization (w=MPL)—a characteristic of an (non-strictly) overpopulated labor market. Moreover, it may be the case that MPL hits the “x” axis without ever crossing the labor supply curve—a strictly overpopulated labor market.

    Alin

  33. Gravatar of ssumner ssumner
    13. April 2011 at 18:01

    Alan, You lost me at the end. But a few comments:

    1. I do understand the common misinterpretation of MPL, and I am pretty sure that Tyler Cowen does as well. But some of his critics may have assumed he was claiming that unemployed workers were unproductive as people–not so.

    2. In my view the MR issue may be important. If firms are fairly monopolistically competitive, then the MR may be fairly low at current output. Combine that with a fairly low MPL relative to the APL, and you’ve got a really low MRPL. Maybe not zero, but pretty close. That would be Tyler’s best argument.

  34. Gravatar of Alan Alan
    13. April 2011 at 20:17

    Scott,

    Thank you very much and agreed on the MR point. About the confusion, fat fingers–a piece from the following was accidentally deleted from the post:


    Now,

    Marginal Revenue Product of Labor -> MRPL = MR x MPL or 0 or even =0(!), the specific case of contention) *at existing employment level’s MPL*.

    The last part referred to the material at the link in comment #3 above which talks about a similar problem related to draft horses. I was only noting that the point of theoretical equilibrium of wages, w, would have to be below subsistence in order to get the horses laid…to rest. The remainder is a comment to N. Georgescu-Roegen’s treatment of “unusual” labor/supply intersection points in “Economic Theory and Agrarian Economics” (http://www.jstor.org/pss/2661989).

  35. Gravatar of Zero Marginal Productivity (ZMP) | socot Zero Marginal Productivity (ZMP) | socot
    13. April 2011 at 20:31

    [...] Posted on 14/04/2011 by socot A very interesting point in macroeconomics is made by Scott Sumner (http://www.themoneyillusion.com/?p=8360) regarding the possibility and plausibility of zero [...]

  36. Gravatar of ssumner ssumner
    16. April 2011 at 08:08

    Alan, Thanks for clarifying that.

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