Reducing Meat Consumption?

A couple weeks ago, The Economist ran this story about people’s stated efforts to reduce meat consumption. Here is their key graph, which shows demographic breakdowns in how people responded to this question.

These demographic results are largely consistent with many of the survey results I’ve generated over the past few years. For example, here are demographic breakdowns of people who self declare as vegetarian/vegan vs. meat eater. Like the study mentioned in The Economist, we find politically liberal individuals are much more likely to be vegetarians/vegans as compared to politically conservative individuals.

Also, see this study where I estimated beef demand. Again, demand for steak and ground beef increases the more conservative the respondent.

More broadly, the study mentioned by The Economist suggests:

“Twenty-seven per cent of respondents in our survey say they have made an effort to reduce their consumption of meat in the past year.”

That’s a bit of a strange framing because if you look at USDA data on consumption (or “disappearance”), over the past four to five years it has been increasing. As for measures of meat demand, such as these complied by Glynn Tonsor at K-State, demand today for beef and pork is quite a bit higher than in 2010 or 2011.

Maybe, this is a way of saying that I’m skeptical of questions like that in The Economist that ask, in a somewhat leading way, how much are one trying to reduce consumption of X. A more balanced question shows much different results.

For example, see the results of this study on pork I conducted with Glynn Tonsor, Ted Schroeder, and Dermot Hayes for the Pork Board. We report:

“One of the initial questions asked respondents, “Over the past five years, has your consumption of pork chops increased or decreased?” 32.9% indicated consumption had increased, 57.5% responded “stayed the same,” and the remaining 9.6% indicated consumption had decreased. ”

For the 9.6% who said “decrease”, we asked why, and the most common response was, “Other meat options have become more attractive.” So, in this case, even among people who said they were eating less pork, it’s because they’re eating more of other types of meat.

Or, here are the results of a survey I conducted last year, where I asked the same question but this time about chicken consumption. The result?

“One of the initial questions asked respondents, “Over the past five years, has your consumption of chicken increased or decreased?” 47.4% indicated consumption had increased, 48.5% responded “stayed the same,” and the remaining 4.1% indicated consumption had decreased. ”

The most commonly stated reason among the 4.1% who said “decrease” was “Chicken has become less tasty.”

It’s interesting that when given the option of “increase or decrease”, I only find 9.6% of pork consumers and 4.1% of chicken consumers say they’re decreasing consumption, both of which are far lower than the 27% suggested by The Economist.

Turkey Prices

It’s almost Thanksgiving. That means its time for the annual news stories on trends in turkey prices. I put out a story a week or so ago that has been picked up in a number of print, radio, and TV spots. The headline is that this November’s turkey prices are expected to be at a 10 year low.

For a bit of background and context, this claim is based on average price data reported by the Bureau of Labor Statistics (BLS). These data are collected as a part of the BLS’s effort to construct the consumer price index (CPI) and monitor inflation. Here is a graph of inflation-adjusted retail prices for frozen turkey for the past eleven years in the months of October, November, and December.

The blue line represents November prices (we don’t yet know the 2018 November’s price, so it is foretasted based on past price movements). This year’s November price is expected to be around $1.45/lb, which is about 22% lower than the peak in 2013 and about 6% lower than back in 2008.

A couple comments based on the above graph. Interestingly, prices tend to fall from October to November. On average during the past 10 years, November prices are about 8% lower than October prices. At first blush, this might seem a bit strange. Doesn’t demand for turkey increase during thanksgiving, which should drive up turkey prices? Yes, but other factors are also at play. For one, retailers may strategically cut the price of turkey to get people in the door to buy the rest of their thanksgiving meal - i.e., turkey is potentially a “loss leader.” Second, producers expect the demand shift and produce more birds around the holiday. Here is a figure from the Livestock Marketing Information Center (LMIC) based on USDA data. As you can see, turkey production tends to peak each year in November.

I should note that the American Farm Bureau puts out an annual cost of Thanksgiving, and their estimates are for prices to be down this year as well. The USDA Economic Research Service estimates overall food price inflation and they’re also projecting historically low price increases. For 2018, they forecast prices for food at home to only rise only between 0 and 1% for the year; the 20 year average is about 2.1%. Why the low food prices?

One answer is that food production in general, and turkey production in particular, has become much more productive. We get more using less. Here is data again from the LIMC and USDA showing the number of turkeys slaughtered in federally inspected facilities since 1960 alongside the calculated number of pounds produced per turkey.

Prior to the 1970s, turkeys averaged about 15 lbs/bird, a figure that’s increased almost linearly since the 1980s up to the point now where we are over 30 lbs/bird. In fact, compared to the mid 1990’s we now have about 5 million fewer turkeys slaughtered every month even though we’re actually producing more total lbs of turkey today than in the early 1990s. Here’s total lbs of production over time.

The other big factor driving the recent affordability of turkey and other foodstuffs is that commodity (e.g., corn, soy, wheat) prices are low and have been low for the past couple years. Of course, this can’t be the only explanation because the price of retail foodstuffs is comprised of much more than just commodities, so it must mean that the prices of other inputs like labor, energy, and packaging have also remained relatively affordable.

Arbitraging the Market for Food Fears

A couple weeks ago, the best selling author Michael Lewis was on campus, and I went to listen to him talk. I’ve read several of Lewis’ books, and it was interesting to hear him talk about some of the underlying themes that united them.

In his 2017 book, the Undoing Project, Lewis writes the history of Kahneman and Tversky and the development of behavioral economics, a field that posits people do not always make rational decisions. In an earlier book, Moneyball (published in 2004), a few stat/econ types realized baseball teams were leaving money on the table by ignoring data on what really drives team wins. One team manager, Billy Beane, attempted to arbitrage the market for players by buying “undervalued” players and putting them to higher-valued use. In another earlier book, the Big Short (published in 2010), Lewis talks about the people who made big bucks on the financial crisis by recognizing that markets were “mispricing” the risks of systemic mortgage failures. In some ways the books are out of order because Lewis’s earlier books described how various people made serious money from the sorts of behavioral biases that Kahneman, Tversky, and others uncovered.

What’s this got to do with food?

Many of the systematic biases that lead people to mis-price baseball players and mortgage-backed securities are likely leading people to mis-price foods made with new technologies. Take GMOs. A Pew study found 88% of scientists but only 37% of the public thought GMOs are safe to eat. Is it possible scientists are wrong and the public is right? Sure, but if you had to place a bet, where would you put your money?

Or, let’s take at a widely studied behavioral bias - the tendency for people to exaggerate the importance of low-probability risks. The propensity to overweight low probability events was one of the cornerstones of prospect theory, which was introduced by Kahneman and Tversky. This theory is sometimes credited as herding the birth of modern-day behavioral economics, and the paper was a key contributor to Kahneman later winning a Nobel Prize. If there is a 1% chance of an outcome occurring, when making decisions, people will often “irrationally” treat it as a 5% or 10% chance. There are many, many studies demonstrating this phenomenon.

Oddly, I have never seen a behavioral economists use this insights to argue that fears over growth hormones, GMOs, pesticides, preservatives, etc. are overblown. However, there are many food and agricultural scientists who argue that many of our food fears are, in fact, irrational in the sense that public perceptions of risk exceed the scientific consensus.

Now, getting back to Michael Lewis’s books on the people who figured out how to profit from behavioral biases in fields as divergent as baseball players and mortgage-backed securities, if we really think people are irrationally afraid of new food technologies, is it possible to put our money where our mouth is? Or, buy fears low and sell them high?

Here are a few half-baked thoughts:

• If people are worried about the safety of food ingredients and technologies, shouldn’t they be willing to buy insurance to protect against the perceived harms? And if consumers are overly worried, they should be willing to pay more for insurance than it actually costs to protect against such harms. If we believe this is the case, then creating insurance markets for highly unlikely outcomes should be a money-making opportunity. On the plus side, such markets might also take some of the fear out of buying foods with such technologies since people can hedge their perceived risks.

• Let’s say your Monsanto (now Bayer), Syngenta, BASF, or another seed/chemical company. What can you do to assuage consumers’ fears of your technologies, particularly if you believe the perceive risks are exaggerated? Why not offer up a widely publicized bond that will be held in trust in case some adverse event happens within a certain period of time? (This is like when contractors or other service suppliers attempt to gain trust by being bonded). If it is really true that consumers’ fears are exaggerated, the bond won’t be paid out (at least not in full), and will revert back to the company.

• Did you know that it is possible to invest in lawsuits? Investors, whose money is used to front the legal bills, earn a portion of the payout if a plaintiff wins a settlement against a corporation or other entity responsible for some harm. The “price” of such investments is likely to rise the greater the public’s perceived odds of winning the case, which presumably related to perceptions of underlying risks. I can imagine institutions or markets arising that would enable investors to short such investments - to make money if the plaintiff losses the case. The current Monsanto-glyphosate verdict not withstanding, shouldn’t it be the case that one could profitability short lawsuits surrounding the safety of food and farm technologies if the fears around them are indeed overblown?

Other ideas?

The Cost and Market Impacts of Slow Growth Broilers

I just finished up a new working paper (available here) with my Purdue ag econ colleague Nathan Thompson and Shawna Weimer, a soon-to-be assistant professor of poultry science at the University of Maryland.

Readers may recall my post from a couple months ago on consumer demand for slow-growth chickens. This new paper focuses on producer costs of switching to slow-growth broiler chicken. Here’s the motivation from the paper (references removed for readability):

“While modern broilers only live about six weeks, there are concerns that the bird’s legs are unable to adequately support the larger bodyweights, leading to pain and an inability to exhibit natural behaviors. As a result of such findings, animal advocacy organizations have begun to pressure food retailers to use slower growing breeds, European regulators have encouraged slow growth broilers, national media attention has begun to focus on the issue, and some animal welfare standards and labels have begun to require slower growing broiler breeds. There has been some consumer research on demand for this attribute, but little is known about the added production costs associated with slow growth chickens.”

We obtained data from commercial breeding companies on two slow growth broiler breeds (called Ranger Classic and Ranger Gold) and data on two modern fast growing breeds (called Ross 308 and Cobb 500). Here are the growth curves for the four broiler breeds:

The two slow growth breeds are, well, slower growing. The slower-growing breeds take 54 and 59 days, respectively to reach 6 lbs, whereas the faster growing breeds both hit this target weight in about 41 days.

These growth data are combined with data on feed intake, prices, assumptions about stocking density, and more, and we calculate costs and returns under a number of different scenarios. Here are the main results for the most likely scenario where producers choose the number of days to feed broilers so as to maximize net returns and where slow growth broilers have a more generous stocking density than fast growth broilers, as dictated in many animal welfare guidelines.

About 17.45 lbs/ft2/year (or 73%) more chicken on a dressed weight basis is provided by the two fast vs. two slow growth productions systems, on average. Thus, substantially more barn space, or square footage, would be required to produce the same volume of chicken from slow as compared to fast growth breeds. Costs of production average $0.54/lb for the two slow growth breeds and average $0.47/lb for the two fast growth breeds, implying costs are 14% higher per pound for the slower growth breeds. Fast growth breeds are substantially more profitable - generating returns about twice as high per square foot than the slower growth breeds. We calculate that the slower growth broilers would need to obtain wholesale price premiums of $0.285/lb and $0.363/lb to achieve the same profitability as the best performing fast growth breed.

We also use these estimates to calculate potential market impacts that would occur if the entire industry transitioned from fast to slow growth broiler breeds. Under the most likely scenario, we calculate that converting to slow growth breeds would increase retail chicken prices by 1.17% and reduce the amount of retail chicken sold by 0.91%, resulting in losses in producer profits of $3.5 billion/year. We also calculate that consumers would be worse off by $630 million/year, assuming their demand for chicken doesn’t change in response to the switch from slow to fast growth. Increases in consumer willingness-to-pay of 8.5% would be needed to offset the adverse effect on producer profits.

Organic Food Consumption and Cancer

A couple of days ago, JAMA Internal Medicine published a paper looking at the relationship between stated levels of organic food consumption and cancer among a sample of 68,946 French consumers.

The paper, and the media coverage of it, is frustrating on many fronts, and it is symptomatic of what is wrong with so many nutritional and epidemiological studies relying on observational, self reported data without a clear strategy for identifying causal effects. As I wrote a couple years ago:

“Fortunately economics (at least applied microeconomics) has undergone a bit of credibility revolution. If you attend a research seminar in virtually any economics department these days, you’re almost certain to hear questions like, “what is your identification strategy?” or “how did you deal with endogeneity or selection?” In short, the question is: how do we know the effects you’re reporting are causal effects and not just correlations.

Its high time for a credibility revolution in nutrition and epidemiology.”

Yes, Yes, the title of the paper says “association” not “causation.” But, of course, that didn’t prevent the authors - in the abstract - from concluding, “promoting organic food consumption in the general population could be a promising preventive strategy against cancer” or CNN from running a headline that says, “You can cut your cancer risk by eating organic.”

So, first, how might this be only correlation and not causation? People who consume organic foods are likely to differ from people who do not in all sorts of ways that might also affect health outcomes. As the authors clearly show in their own study, people who say they eat a lot of organic food are higher income, are better educated, are less likely to smoke and drink, eat much less meat, and have overall healthier diets than people who say they never eat organic. The authors try to “control” for these factors in a statistical analysis, but there are two problems with this. First, the devil is in the details and the way these confounding factors are measured and interact could have significant effects. More importantly, some of these missing “controls” are things like overall health consciousness, risk aversion, social conformity, and more. This leads to a second more fundamental problem. These unobserved factors are likely to be highly correlated with both organic food consumption and cancer risk, and thus the estimated effect on organic is likely biased. There are many examples of this sort of endogeneity bias, and failure to think carefully about how to handle it can lead to effects that are under- or over-estimated and can even reverse the sign of the effect.

To illustrate, suppose an unmeasured variable like health consciousness is driving both organic purchases and cancer risk. A highly health conscious person is going to undertake all sorts of activities that might lower cancer risks - seeing the doctor regularly, taking vitamins, being careful about their diet, reading new dietary studies, exercising in certain ways, etc. And, such a person might also eat more organic food, thus the correlation. The point is that even if such a highly health conscious person weren’t eating organic, they’d still have lower cancer risk. It isn’t the organic causing the lower cancer risk. Or stated differently, if we took a highly health UNconscious person and forced them to eat a lot of organic, would we expect their cancer risk to fall? If not, this is correlation and not causation.

Ideally, we’d like to conduct a randomized controlled trial (RCT) (randomly feed one group a lot of organic and another group none and compare outcomes), but these types of studies can be very expensive and time consuming. Fortunately, economists and others have come up with creative ways to try to address the unobserved variable and endogeneity issues that gets us closer to the RCT ideal, but I see no effort on the part of these authors to take these issues seriously in their analysis.

Then, there are all sorts of worrying details in the study itself. Organic food consumption is a self-reported variable measured in a very ad-hoc way. People were asked if they consumed organic most of the time (people were given 2 points), occasionally (people were given one point), or never (no points), and this was summed across 16 different food categories ranging from fruits to meats to vegetable oils. Curiously, when the authors limit their organic food variable to only plant-based sources (presumable because this is where pesticide risks are most acute), the effects for most cancers diminishes. It is also curious that the there wasn’t always a “dose response” relationship between organic consumption scores and cancer risk. Also, when the authors limit their analysis to particular sub-groups (like men), the relationship between organic consumption and cancer disappears. Tamar Haspel, a food and agricultural writer for the Washington Post, delves into some of these issues and more in a Tweet-storm.

Finally, even if the estimated effects are “true”, how big and consequential are they? The authors studied 68,946 people, 1,340 of whom were diagnosed with cancer at some point during the approximately 6 year study. So, the baseline chance of any getting any type of cancer was (1340/68,946)*100 = 1.9%, or roughly 2 people out of 100. Now, let’s look at the case where the effects seem to be the largest and most consistent across the various specifications, non-Hodgkin lymphomas (NHL). There were 47 cases of NHL, meaning there was a (47/68,946)*100 = 0.068% overall chance of getting NHL in this population over this time period. 15 and 14 people, respectively, in the lowest first and second quartiles of organic food scores had NHL, but 16 people in the third highest quartile of organic food consumption had HCL. When we get to the highest quartile of stated organic food scale, the number of people with HCL now dropped to only 2. After making various statistical adjustments, the authors calculate a “hazard ratio” of 0.14 for people in the lowest vs. highest quartiles of organic food consumption, meaning there was a whopping 86% reduction in risk. But, what does that mean relative to the baseline? It means going from a risk of 0.068% to a risk of 0.068*0.14=0.01%, or from about 7 in 10,000 to 1 in 10,000. To put these figures in perspective, the overall likelihood of someone in the population dying from a car accident next year are about 1.25 in 10,000 and are about 97 in 10,000 over the course of a lifetime. The one-year and lifetime risk from dying from a fall on stairs and steps is 0.07 in 10,000 and 5.7 in 10,000.

In sum, I'm not arguing that eating more organic food might not be causally related to reduced cancer risk, especially given the plausible causal mechanisms. Rather, I’m arguing that this particular study doesn’t go very far in helping us answer that fundamental question. And, if we do ultimately arrive at better estimates from studies that take causal identification seriously that reverse these findings, we will have undermined consumer trust by promoting these types of studies (just ask people whether they think eggs, coffee, chocolate, or blueberry increase or reduce the odds of cancer or heart disease).