biased NBA referees, again

Last year I posted on a paper by Joseph Price (BYU) and Justin Wolfers (Penn) that showed that NBA referees were racially biased. Price is again identifying biases amongst NBA refs, this time with coauthors Marc Remer (Johns Hopkins) and Daniel Stone (Oregon State).

The new working paper finds evidence that NBA referees are more likely to call fouls in favor of (1) home teams, (2) teams that are losing, and (3) teams that are down in the number of playoff games won. To account for the possibility that the three types of biases may be due to players playing differently when they are at home or behind, the authors look at play-by-play data which allows them to distinguish between discretionary turnovers (e.g., shooting fouls, charging) and non-discretionary turnovers (e.g., steals and bad passes). They show that the biases are due to the referees, not players.

The authors argue that each of these biases may increase league profits by (1) making home games more exciting, (2) making games more exciting in general, and (3) extending the number of games in the season. However, they find no evidence that the biases are explicit, and conclude that they are likely implicit.

high school sports and teen pregnancy

Females who participate in sports are less likely to get pregnant than ones who do not. This has largely been used to insinuate that by participating in sports, a girl decreases her chances of getting pregnant. In a recent working paper, Joseph Price (BYU), Daniel Simon (Cornell), and Betsey Stevenson (Penn) find the flaw in this logic.

The authors point out that girls who decide to participate in sports may be significantly different from the typical girl who does not participate. They are likely more confidence, for example. We observe that sports participants are less likely to get pregnant; this is different from saying that a girl who plays sports is less likely to get pregnant than the same girl if she was not on a sports team.

It turns out that sports participation actually increases the pregnancy rate among girls. To show this, the study looks at the effect of Title XI, and the introduction of additional female sports participation, on pregnancy rates. From the paper's abstract:

We find that a 10 percentage point increase in the fraction of girls playing sports in a state increases the teen birth rate by 0.3 percentage points (about a 10% increase). However, there are racial differences in the effect of sports participation. The increase in the teen birth rate is most pronounced for white young women with some suggestive evidence that sports decreases teen birth rates among black young women.

Download it here.

should we tax or cap political contributions?

In the spirit of unabashed self-promotion, here is a summary of some of my own research, as it appeared in the University of Miami B-School Buzz:

With the U.S. Supreme Court expected to address campaign finance reform in its next term, new research from Christopher Cotton, an assistant professor of economics, offers fresh insight on the issue. The study uses game theory to compare two reform options: contribution limits and taxing campaign contributions. His conclusion? Taxing campaign contributions is the better solution. The research is published in the August issue of the Journal of Public Economics.

Link to working paper version or final version on journal website.

why are divorce rates higher in urban areas?

The divorce rate is higher in urban areas than in rural areas. Why is this? It could be that the abundance of potential partners in urban areas cause people to "trade up" more often, or to cheat on their spouses more often. Or maybe, people in rural areas are more likely to think of divorce as a non-option.

In a new paper, appearing in the Scandinavian Journal of Economics, Pieter Gautier (Vrije Universiteit), Michael Svarer (Aarhus University), and Coen Teulings (Netherlands Bureau for Economic Policy Analysis) propose another possibility. Maybe couples who are more content with their relationships are more likely to move out of the city, while those who are less content are more likely to stay in the city. This makes a lot of sense. People often leave the city to focus more on family life, something you are more likely to do when you are happy with your spouse. The research shows that once your control for this sorting effect, there is no distinguishable difference in divorce rate.

Link to the paper here.

longer school days and student performance

In the current issue of Economics of Education Review, Cristián Bellei (U Chile) considers whether lengthening the school day increases student achievement. Looking at a change in the length of a school day in Chile, the paper shows that more classroom time increases achievement in mathematics and language. This impact is larger for public school, rural, and high-achieving students.

Link to the paper here.