The economics world has countless people doing fascinating research, and as much as we try at Planet Money, there's a lot of stuff that we don't end up covering. So periodically, we like to do a little roundup of interesting research we've come across and share it with you in the Planet Money newsletter.
Welcome to Planet Money Paperpalooza. OK, no. Planet Money Researchstock. Hmmm. Paperchella? Fine, we still don't have a good name for this recurring newsletter series. Please send suggestions: planetmoney@npr.org. And fun ideas for a logo ;)
Anyways, today in the Planet Money newsletter: five recent papers that we found interesting and worth sharing.
A long economic history of firewood in America
Why we liked this paper: a deep, historical dive into something we rarely think about — firewood.
Believe it or not, this one is buzzy and making the rounds. A recent working paper, "Firewood in the American Economy: 1700 to 2010," really got our curiosity burning. We just wanted to huddle around it and bask in its insights.
Carnegie Mellon University economist Nicholas Muller explains how central firewood used to be in the American economy. Firewood was humanity's main energy source for centuries.
Yet, despite that, scholars have long lacked solid statistics about firewood prices over the long sweep of history. Muller explains that one big reason for this is that many Americans chopped down wood themselves. They often didn't buy it in the market, so historical prices have been hard to come by.
But as cities grew, many Americans could no longer chop down wood themselves. And so market transactions for firewood began to take place. Newspapers began publishing firewood prices in their classified sections. In this study, Muller finds more than 6,000 price quotes from historical sources and constructs a price index for firewood going all the way back to 1700.
This paper offers a bundle — ahem — of interesting facts, including:
+ Around 1860, firewood accounted for around 85% of energy consumption in the United States.
+ In the 1830s, the U.S. started to see large-scale coal production. However, coal remained relatively expensive compared with firewood, so it took a while for coal to dominate the U.S. energy market.
+ During the early- to mid-19th century, the price of firewood outpaced overall inflation. Firewood kept getting more and more expensive. Meanwhile, coal got cheaper and cheaper. "The change in relative prices of these fuels appears to have played a fundamental role in the transition from wood to coal," Muller writes.
+ After 1870, demand for firewood began declining, and coal became the hottest energy source in the nation. By 1900, coal accounted for 71% of energy use in the United States. After World War I, Muller writes, coal's dominance began being eroded away by oil and natural gas.
This firewood paper reminded us of a classic paper from Yale University economist William Nordhaus, who calculated how the cost of lighting changed over a thousand years. Check out this Planet Money episode about it.
Political spending in the wake of school shootings
Why we liked this paper: a sobering look at interest group political spending in the wake of tragedies.
Another new study is … darker. It's titled "Financial Firepower: School Shootings and the Strategic Contributions of Pro-Gun PACs." The economists Eric Baldwin, Takuma Iwasaki and John Donohue look at what happens to political spending in the wake of school shootings.
Between 2000 and 2024, the economists write, there were more than 500 school shootings in the U.S. that resulted in at least one fatality. "Yet rather than leading to significant policy change, these tragedies rarely result in more than empty promises," the economists write. They point to one significant reason for this.
The economists find that pro-gun political action committees "increase contributions by 30.2% to [congressional] candidates in districts with fatal school shootings."
This spending appears to be strategic. The economists find that pro-gun PACs increase spending only really in congressional districts that see fatal school shootings, not nonfatal school shootings or other mass shootings. The PACs' spending ramps up as elections approach and is mostly concentrated in congressional districts where elections are competitive.
NIMBYism spreads to the Sunbelt?
Why we liked this paper: It makes America's worsening housing affordability crisis make more sense.
The research of economists Ed Glaeser and Joseph Gyourko has long shined a spotlight on the problem of housing supply in the United States. We're not building enough housing, and it has been causing a housing affordability crisis.
For a long time, this lack of new housing seemed to be mainly a problem in coastal cities. In 2005, Glaeser and Gyourko published a study that divided America's housing market into three big regions: high-cost, high-demand coastal markets that did not build a lot of new housing and saw explosive growth in housing costs (like San Francisco, Los Angeles, New York and Boston); low-demand, declining industrial cities (like Detroit and Cleveland); and roaring Sunbelt markets that built a lot of new housing (like Miami, Atlanta, Dallas and Phoenix). The building of new housing in these Sunbelt areas helped moderate price hikes even as demand grew.
In this new study, Glaeser and Gyourko find that something big has changed in the Sunbelt over the last couple of decades: They've begun to look a lot more like coastal areas in their lack of construction of new housing. The result: an explosion of home prices.
"From 2000-2024, Miami, Tampa and Phoenix ranked 1st, 5th, and 9th, in price growth across the twenty areas that make up the S&P CoreLogic Case-Shiller 20 City Composite Home Price NSA Index," the economists write. "Each of these areas experienced more price growth than the New York City area, whose prices still increased by a healthy 70 percent. Between 1975 and 1999, no sunbelt city (outside of California) was among the top twelve of the same 20 markets."
Why have Sunbelt regions begun to look more like coastal regions in recent years, with a lower rate of new housing construction and an explosion of home prices? The economists hypothesize that, basically, NIMBYism has spread there. They suggest that "wealthier or better educated residents" have moved in and altered the regulatory environment, making it harder to build housing.
The economists find that, if the rate of new housing construction between 2000 and 2020 looked like it did between 1980 and 2000, "America would have 15 million more housing units."
"The key driver appears to be that the intensity of housing production has dropped substantially over time, especially in many expanding sunbelt markets that were once housing production superstars," the economists write. "More generally, there is a marked convergence in the pace of housing unit production across markets throughout the country: Miami has become far more like Los Angeles."
Interestingly, coastal regions have begun to reckon with the regulatory barriers to building new housing. Last week, California Gov. Gavin Newsom took actions to roll back environmental regulations that have held back development in California.
The economic effects of Native American casinos
Why we liked this paper: It provides an interesting perspective on Native American casinos.
Native American communities have long struggled economically. In the late 1980s and early 1990s, tribal leaders began to embrace an industry to help lift them up: casinos.
A new working paper from economists Randall Akee, Maggie R. Jones and Emilia Simeonova categorizes tribal gaming as a kind of "place-based policy," a program aimed at economically developing an impoverished community as opposed to directly helping individuals.
On that front, tribal gaming seems to have been remarkably successful. It's now an industry that rakes in more than $40 billion a year. And the economists find that it is a real engine of opportunities for Native Americans. They find "significantly higher employment of American Indians in the Accommodations, Food Services, Arts and Entertainment Industries compared with non-casino reservation ZIP codes in the same state. Further, we find an increase in wages for AIAN workers in these same industries, suggesting both an expansion of employment and better compensation in this sector for American Indians." Casinos also bring in money that tribes use in various ways to help their communities, including cash transfers to tribe members, infrastructure, education and business investment.
Longer kindergarten school days boost mothers' work hours
Why we liked this paper: It provides more evidence on a way to close the gender pay gap.
Over the last decade, there has been a lot of economic research suggesting that the gender pay gap between women and men is driven by the fact that women, on average, continue to bear most of the burden of family caregiving. Claudia Goldin, who won the 2023 Nobel Memorial Prize in Economic Sciences, has done a lot of important research in this area. And one of her policy proposals to close the gender pay gap is pretty simple: extend school hours. That, she hypothesizes, will free up more time for women to pursue their careers and earn money.
A new study by economists Chloe Gibbs, Jocelyn S. Wikle and Riley Wilson offers more evidence supporting this idea. The working paper is titled "A Matter of Time? Measuring Effects of Public Schooling Expansions on Families."
The economists look at the effects of a remarkable change in early childhood education: the dramatic expansion of kindergarten from half day to full day over the last few decades. Since 1992, the share of American kindergartners in full-day schooling has almost doubled, from 43% to 83%.
The economists do a bunch of impressive statistical work to look at the casual effect of this change on family work hours. Interestingly, they find that this change hardly affected fathers, on average. They find that men with kids in half-day kindergarten "actually spend more time at work than fathers of full-day kindergarten students."
However, the economists found a big change for mothers: "Our findings suggest that expansions in full-day kindergarten can explain approximately 2 percentage points, or 24 percent, of the 8.5 percentage-point increase in employment among mothers of 5- and 6-year-olds between 1992 and 2022."
P.S. If you come across interesting economics papers and want us to include them in future newsletters like this one, send away! Email us at planetmoney@npr.org.
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