It’s unusual for the expert opinions on an issue to range all the way from zero to 100%.
Economists using an instrumental variable approach found that digital piracy did not hurt record sales in the 2000’s. Hammond (2014) found, incredibly, that file-sharing increased record sales. The picture above is of an article critiquing the Oberholzer-Gee and Strumpf (2007) conclusion that was published by a top journal.
Liebowitz reports that music industry professionals believed that digital piracy was the primary or complete cause of the decline of record sales. One would think that industry insiders have accurate data on the problem and a decent mental model relating the variables together.
The estimated effect of music file-sharing ranged from helping music sales to completely eliminating them. Where else can we find so much disagreement on the answer to a narrow empirical question?
That’s the title of a blockbuster new paper by Shikhar Singla. The headline finding is that increased regulatory costs are responsible for over 30% of the increase in market power in the US since the 1990’s. That’s a big deal, but not what I found most interesting.
One big advance is simply the data on regulation. If you want to measure the effect of regulation on different industries, you need to come up with a way to measure how regulated they are. The crude, simple old approach is to count how many pages of regulation apply to a broad industry. The big advance of Mercatus’ RegData was to use machine learning to identify which specific industry is being discussed near “restrictive words” in the Code of Federal Regulation that indicate a regulatory restriction is being imposed. But not all regulatory words (even restrictive ones) are created equal; some impose very costly restrictions, most impose less costly restrictions, and some are even deregulatory. Singla’s solution is to take the government’s estimates of regulatory costs and apply machine learning there:
This paper uses machine learning on regulatory documents to construct a novel dataset on compliance costs to examine the effect of regulations on market power. The dataset is comprehensive and consists of all significant regulations at the 6-digit NAICS level from 1970-2018. We find that regulatory costs have increased by $1 trillion during this period.
The government’s estimates of the costs are of course imperfect, but almost certainly add information over a word-count based approach. Both approaches agree that regulation has increased dramatically over time. How does this affect businesses? Here’s what’s highlighted in the abstract:
We document that an increase in regulatory costs results in lower (higher) sales, employment, markups, and profitability for small (large) firms. Regulation driven increase in con- centration is associated with lower elasticity of entry with respect to Tobin’s Q, lower productivity and investment after the late 1990s. We estimate that increased regulations can explain 31-37% of the rise in market power. Finally, we uncover the political economy of rulemaking. While large firms are opposed to regulations in general, they push for the passage of regulations that have an adverse impact on small firms
More from the paper:
an average small firm faces an average of $9,093 per employee in our sample period compared to $5,246 for a large firm
a 100% increase in regulatory costs leads to a 1.2%, 1.4% and 1.9% increase in the number of establishments, employees and wages, respectively, for large firms, whereas it leads to 1.4%, 1.5% and 1.6% decrease in the number of establishments, employees and wages, respectively for small firms when compared within the state-industry-time groups. Results on employees and wages provide evidence that an increase in regulatory costs creates a competitive advantage for large firms. Large firms get larger and small firms get smaller.
The fact that large firms benefit while small firms are harmed is what drives the increase in concentration and market power.
What I like and dislike most about this paper is the same thing: its a much better version of what Diana Thomas and I tried to do in our 2017 Journal of Regulatory Economics paper. We used RegData restriction counts to measure how regulation affected the number of establishments and employees by industry, and how this differed by firm size. I wish I had thought of using published regulatory cost measures like Singla does, but realistically even if I had the idea I wouldn’t have had the machine learning chops to execute it. The push to quantify what “micro” estimates mean for economy-wide measures is also excellent. I hope and expect to see this published soon in a top-5 economics journal.
Thinking about one of my older papers today, since I just heard it won the Eckstein award for best paper in the Eastern Economic Journal in 2019 & 2020.
One big selling point of the Affordable Care Act was that by offering more non-employer-based options for health insurance, it would free people who felt locked into their jobs by the need for insurance. This would free people up to leave their jobs and do other things like start their own businesses. Did the ACA actually live up to this promise?
It did, at least for some people. The challenge when it comes to measuring the effect of the ACA is that it potentially affected everyone nationwide. If entrepreneurship rises following the implementation of the ACA in 2014, is it because of the ACA? Or just the general economic recovery? Ideally we want some sort of comparison group unaffected by the ACA. If that doesn’t really exist, we can use a comparison group that is less affected by it.
That’s what I did in a 2017 paper focused on younger adults. I compared those under age 26 (who benefit from the ACA’s dependent coverage mandate) to those just over age 26 (who don’t), but found no overall difference in how their self-employment rates changed following the ACA.
In the 2019 Eastern Economic Journal paper, Dhaval Dave and I instead consider the effect of the ACA on older adults. We compare entrepreneurship rates for people in their early 60’s (who might benefit from the availability of individual insurance through the ACA) with a “control group” of people in their late 60’s (who are eligible for Medicare and presumably less affected by the ACA). We find that the ACA led to a 3-4% increase in self-employment for people in their early 60’s.
Why the big difference in findings across papers? My guess is that it’s about age, and what age means for health and health insurance. People in their 60s are old enough to have substantial average health costs and health insurance premiums, so they will factor health insurance into their decisions more strongly than younger people. In addition, the community rating provisions of the ACA generally reduced individual premiums for older people while raising them for younger people.
In sum, the ACA does seem to encourage entrepreneurship at least among older adults. At the same time, our other research finds that the employer-based health insurance system still leads Americans to stay in their jobs longer than they would otherwise choose to.
I’m reading The Property Species by Bart Wilson. I like chapter 4 “What is Right is Not Taken Out of the Rule, but Let the Rule Arise Out of What Is Right,” partly because I got to play a small part in this line of research.
Along with several coauthors, Bart Wilson has run experiments in which players have the ability to make and consume goods. According to the instructions that all players read at the beginning of the experiment, “when the clock expires… you earn cash based upon the number of red and blue items that have been moved to your house.”
Property norms can emerge in these environments, and sometimes subjects take goods from each other in an action that could be called “stealing.” The experimental instructions do not contain any morally loaded words like “stealing,” but subjects use that word to describe the activities of their counterparts.
Here is a conversation from the transcript of the chat room players can use to communicate while they produce and trade digital goods:
E: do you want to do this right way?
F: wht is the right way
E: the right way is I produce red you make blue then we split it nobody gets 100 percent profit but we both win
Since early in graduate school I’ve kept a running list of ideas for economics papers I’d like to write and publish some day. I’ve written many of the papers I planned to, and been scooped on others, but the list just keeps growing. As I begin to change my priorities post-tenure, I decided it was time to publicly share many of my ideas to see if anyone else wants to run with them. So I added an ideas page to my website:
Steal My Paper Ideas! I have more ideas than time. The real problem is that publishing papers makes the list bigger, not smaller; each paper I do gives me the idea for more than one new paper. I also don’t have my own PhD students to give them to, and don’t especially need credit for more publications. So feel free to take these and run with them, just put me in the acknowledgements, and let me know when you publish so I can take the idea off this page.
Here’s one set of example ideas:
State Health Insurance Mandates: Most of my early work was on these laws, but many questions remain unanswered. States have passed over a hundred different types of mandated benefits, but the vast majority have zero papers focused on them. Many likely effects of the laws have also never been studied for any mandate or combination of mandates. Do they actually reduce uncompensated hospital care, as Summers (1989) predicts? Do mandates cause higher deductibles and copays, less coverage of non-mandated care, or narrower networks? How do mandates affect the income and employment of relevant providers? Can mandates be used as an instrument to determine the effectiveness of a treatment? On the identification side, redoing older papers using a dataset like MEPS-IC where self-insured firms can be used as a control would be a major advance.
You can find more ideas on the full page; I plan to update to add more ideas as I have them and to remove ideas once someone writes the paper.
Thanks to a conversation with Jojo Lee for the idea of publicly posting my paper ideas. I especially encourage people to share this list with early-stage PhD students. It would also be great to see other tenured professors post the ideas they have no immediate plans to work on; I’m sure plenty of people are sitting on better ideas than mine with no plans to actually act on them.
This discovery and the examples provided are by graduate student Will Hickman.
Although many academic researchers don’t enjoy writing literature reviews and would like to have an AI system do the heavy lifting for them, we have found a glaring issue with using ChatGPT in this role. ChatGPT will cite papers that don’t exist. This isn’t an isolated phenomenon – we’ve asked ChatGPT different research questions, and it continually provides false and misleading references. To make matters worse, it will often provide correct references to papers that do exist and mix these in with incorrect references and references to nonexistent papers. In short, beware when using ChatGPT for research.
Below, we’ve shown some examples of the issues we’ve seen with ChatGPT. In the first example, we asked ChatGPT to explain the research in experimental economics on how to elicit attitudes towards risk. While the response itself sounds like a decent answer to our question, the references are nonsense. Kahneman, Knetsch, and Thaler (1990) is not about eliciting risk. “Risk Aversion in the Small and in the Large” was written by John Pratt and was published in 1964. “An Experimental Investigation of Competitive Market Behavior” presumably refers to Vernon Smith’s “An Experimental Study of Competitive Market Behavior”, which had nothing to do with eliciting attitudes towards risk and was not written by Charlie Plott. The reference to Busemeyer and Townsend (1993) appears to be relevant.
Although ChatGPT often cites non-existent and/or irrelevant work, it sometimes gets everything correct. For instance, as shown below, when we asked it to summarize the research in behavioral economics, it gave correct citations for Kahneman and Tversky’s “Prospect Theory” and Thaler and Sunstein’s “Nudge.” ChatGPT doesn’t always just make stuff up. The question is, when does it give good answers and when does it give garbage answers?
Strangely, when confronted, ChatGPT will admit that it cites non-existent papers but will not give a clear answer as to why it cites non-existent papers. Also, as shown below, it will admit that it previously cited non-existent papers, promise to cite real papers, and then cite more non-existent papers.
We show the results from asking ChatGPT to summarize the research in experimental economics on the relationship between asset perishability and the occurrence of price bubbles. Although the answer it gives sounds coherent, a closer inspection reveals that the conclusions ChatGPT reaches do not align with theoretical predictions. More to our point, neither of the “papers” cited actually exist.
Immediately after getting this nonsensical answer, we told ChatGPT that neither of the papers it cited exist and asked why it didn’t limit itself to discussing papers that exist. As shown below, it apologized, promised to provide a new summary of the research on asset perishability and price bubbles that only used existing papers, then proceeded to cite two more non-existent papers.
Tyler has called these errors “hallucinations” of ChatGPT. It might be whimsical in a more artistic pursuit, but we find this form of error concerning. Although there will always be room for improving language models, one thing is very clear: researchers be careful. This is something to keep in mind, also, when serving as a referee or grading student work.
The scars of Hurricane Katrina were still obvious eight years afterward when I moved to New Orleans in 2013. Where I lived in Mid-City, it seemed like every block had an abandoned house or an empty lot, and the poorer neighborhoods had more than one per block. Even many larger buildings were left abandoned, including high-rises.
Since then, recovery has continued at a steady pace. The rebuilding was especially noticeable when I spent a few days there recently for the first time since moving away in 2017. The airport has been redone, with shining new connected terminals and new shops. The abandoned high-rise at the prime location where Canal St meets the Mississippi has been renovated into a Four Seasons. Tulane Ave is now home to a nearly mile-long medical complex, stretching from the old Tulane hospital to the new VA and University Medical Center complex. There are several new mid-sized health care facilities, but most striking is that Tulane claims to finally be renovating the huge abandoned Charity Hospital:
The new VA hospital opened in 2016 as mostly new construction, but they’ve now managed to fully incorporate the remnants of the abandoned Dixie Beer brewery:
Dixie beer itself opened a new beer garden in New Orleans East, and just renamed itself Faubourg Brewery. Some streets named for Confederates have also been renamed, though you can still see plenty of signs of the past, like the “Jeff Davis Properties” building on the street renamed from Jefferson Davis Parkway to Norman C Francis Parkway.
Of course, even with all the improvements, many problems remain, both in terms of things that still haven’t recovered from the hurricane, and the kind of problems that were there even before Katrina. The one remaining abandoned high-rise, Plaza Tower, was actually abandoned even before Katrina.
My overall impression is that large institutions (university medical centers, the VA, the airport, museums, major hotels) have been driving this phase of the recovery. The neighborhoods are also recovering, but more slowly, particularly small business. Population is still well below 2005 levels. I generally think inequality has been overrated in national discussions of the last 15 years relative to concerns about poverty and overall prosperity, but even to me New Orleans is a strikingly unequal city; there’s so much wealth alongside so many people seeming to get very little benefit from it.
The most persistent problems are the ones that remain from before Katrina: the roads, the schools, and the crime; taken together, the dysfunctional public sector. Everywhere I’ve lived people complain about the roads, but I’ve lived a lot of places and New Orleans roads were objectively the worst, even in the nice parts of town, and it isn’t close. The New Orleans Police Department is still subject to a federal consent decree, as it has been since 2012. The murder rate in 2022 was the highest in the nation. Building an effective public sector seems to be much harder than rebuilding from a hurricane.
As much as things have changed since 2013, my overall assessment of the city remains the same: its unlike anywhere else in America. It is unparalleled in both its strengths and its weaknesses. If you care about food, drink, music, and having a good time, its the place to be. If you’re more focused more on career, health, or safety, it isn’t. People who fled Katrina and stayed in other cities like Houston or Atlanta wound up richer and healthier. But not necessarily happier.
I expected the meetings would shrink, but I was still surprised by how much they did:
That said, I mostly didn’t notice the smaller numbers on the ground, because most of the missing people are those on the job market, who used to spend most of their time shut away doing interviews anyway. There was still a huge variety of sessions and most seemed well-attended. ASSAs is also still unparalleled for pulling in top names to give talks; I got to talk to Nobel laureate Roger Myerson at a reception. But there may be a trend of the big names being more likely to stay remote:
The big problem with attendance falling to 6k is that they’ve planned years worth of meetings with the assumption of 12k+ attendance. Getting one year further from Covid and dropping mask and vaccine mandates might help some, but the core issue is that 1st-round job interviews have gone remote and aren’t coming back. The best solution I can think of is raising the acceptance rate for papers, which in recent history has been well under 20%.
In terms of the actual economic research, two sessions stood out to me:
How many factors are there in the stock market? Classic work by Fama and French argues for 3 (size, value, and market risk), but the finance literature as a whole has identified a “zoo” of over 500. Two papers presented one after the other at ASSA argued for two extremes. “Time Series Variation in the Factor Zoo” argues that the number of factors varies over time, but is quite high, typically over 20 and sometimes over 100:
In contrast, “Three Common Factors” argues that there really are just 3 factors, though they are latent and not the same as the Fama-French 3 factors. In this case, the whole zoo of factors in the literature is mostly non-robust results driven by p-hacking and a desire to find more factors (fortune and fame potentially await those who do). Overall these asset pricing papers make me want to look into all this myself; when reading them I’m always struck by an odd mix of reactions- “I don’t understand that”, “why would you do it that way, it seems wrong and unnecessarily complicated”, and “why didn’t the field settle such a seemingly basic question decades ago?”.
Hayek: A Life this session covered the new book by Bruce Caldwell (who taught me much of what I know of the history of economic thought) and Hansjoerg Klausinger. Discussants Emily Skarbek and Stephen Durlauf agreed it is surprisingly readable for a long work of original scholarship, calling it a beautifully written 800p pageturner. Vernon Smith asked Caldwell if Hayek read the Theory of Moral Sentiments. Caldwell: “he cited it.” Smith: “but did he read it? Seems like he didn’t understand it very well.” Caldwell agreed he may not have, or if he did it was a German translation.
Vernon Smith’s own talk featured great comments on market instability: instability in markets comes from retrading. Markets are stable when consumers just value goods for their use, like haircuts and hamburgers. The craziness and potential for bubbles and crashes comes in when people are thinking about reselling something, whether it be tulips, stocks, houses, or crypto.
I asked Bruce Caldwell at a reception how he was able to finish writing such a big book that involved lots of archival work and original research. He said “one chapter at a time”, and noted that its fine to write the easiest chapters first to get the ball rolling.
Overall, while ASSA is diminished from the pre-Covid days and I often disagree with the AEAs decisions, its still a top-tier conference, especially when in New Orleans.
In a May post I described a paper my student my student had written on how college majors predict the likelihood of being married and having children later in life.
Since then I joined the paper as a coauthor and rewrote it to send to academic journals. I’m now revising it to resubmit to a journal after referee comments. The best referee suggestion was to move our huge tables to an appendix and replace them with figures. I just figured out how to do this in Stata using coefplot, and wanted to share some of the results:
Many details have changed since Hannah’s original version, and a lot depends on the exact specification used. But 3 big points from the original paper still stand:
Almost all majors are more likely to be married than non-college-graduates
The association of college education with childbearing is more mixed than its almost-uniformly-positive association with marriage
College education is far from uniform; differences between some majors are larger than the average difference between college graduates and non-graduates
Once undergraduates have learned the basics of interpreting regression results, we would like to introduce them to the world of economics research papers. Reading these papers will help reinforce the statistical concepts, and also we want them to get access to the insights in the literature.
Many empirical papers in economics are too long or too difficult to assign to undergraduates, especially if the course is focused more on analytics than economics specifically. Here I provide materials and instructions for teaching two published econ articles to undergraduates. Assume the students have learned the basics of interpreting a regression model (perhaps from a course textbook) but have had few opportunities to apply theses skills or engage in scientific literature.
“The Effects of Attendance on Student Learning in Principles of Economics” is only 4 pages long! Students do not need to read past page 7 of “My Reference Point, Not Yours” to answer the reading guide questions. So, these readings can be assigned outside of class, but I did some of the reading during our class period.
Handing out printed copies of at least one of the papers and my guided questions can make a good classroom activity. If students do not have experience reading tables of regression results, it can be useful to do it together in person.
The questions in the reading guide help students to identify the main variables and hypotheses. Then, students are asked to pull specific results from the tables in the papers. You can customize this list of questions by deleting lines if you do not want to discuss issues like non-linear effects or the null hypothesis.
I provide links below. First is the reading guide with about 30 short-answer questions about the two articles.
Link to download the reading guide that goes with both papers, starting with the shorter one.
3. Two web sources for “My Reference Point, Not Yours” (15 pages in total in the JEBO manuscript, but students do not need to read past page 7 for this exercise, and they can skip the Literature Review section)