Category: Data Source

Crack cocaine as a cause of violence

Crack cocaine markets were associated with substantial increases in violence in the U.S. during the 1980s and 1990s. Using cross-city variation in the emergence of these markets, we show that the resulting violence has important long-term implications for understanding current levels of murder rates by age, sex and race. We estimate that the murder rate of young black males doubled soon after crack’s entrance into a city, and that these rates were still 70 percent higher 17 years after crack’s arrival. We document the role of increased gun possession as a mechanism for this increase. Following previous work, we show that the fraction of suicides by firearms is a good proxy for gun availability and that this variable among young black males follows a similar trajectory to murder rates. Access to guns by young black males explains their elevated murder rates today compared to older cohorts. The long run effects of this increase in violence are large. We attribute nearly eight percent of the murders in 2000 to the long-run effects of the emergence of crack markets. Elevated murder rates for younger black males continue through to today and can explain approximately one tenth of the gap in life expectancy between black and white males.

That is from William N. Evans, Craig Garthwaite, and Timothy J. Moore.

Is NIH funding seeing diminishing returns?

Scientific output is not a linear function of amounts of federal grant support to individual investigators. As funding per investigator increases beyond a certain point, productivity decreases. This study reports that such diminishing marginal returns also apply for National Institutes of Health (NIH) research project grant funding to institutions. Analyses of data (2006-2015) for a representative cross-section of institutions, whose amounts of funding ranged from $3 million to $440 million per year, revealed robust inverse correlations between funding (per institution, per award, per investigator) and scientific output (publication productivity and citation impact productivity). Interestingly, prestigious institutions had on average 65% higher grant application success rates and 50% larger award sizes, whereas less-prestigious institutions produced 65% more publications and had a 35% higher citation impact per dollar of funding. These findings suggest that implicit biases and social prestige mechanisms (e.g., the Matthew effect) have a powerful impact on where NIH grant dollars go and the net return on taxpayers investments. They support evidence-based changes in funding policy geared towards a more equitable, more diverse and more productive distribution of federal support for scientific research. Success rate/productivity metrics developed for this study provide an impartial, empirically based mechanism to do so.

That is by Wayne P. Wals, via Michelle Dawson.

Gendered language

Languages use different systems for classifying nouns. Gender languages assign many — sometimes all — nouns to distinct sex-based categories, masculine and feminine. Drawing on a broad range of historical and linguistic sources, this paper constructs a measure of the proportion of each country’s population whose native language is a gender language. At the cross-country level, this paper documents a robust negative relationship between the prevalence of gender languages and women’s labor force participation. It also shows that traditional views of gender roles are more common in countries with more native speakers of gender languages. In African countries where indigenous languages vary in terms of their gender structure, educational attainment and female labor force participation are lower among those whose native languages are gender languages. Cross-country and individual-level differences in labor force participation are large in both absolute and relative terms (when women are compared to men), suggesting that the observed patterns are not driven by development or some unobserved aspect of culture that affects men and women equally. Following the procedures proposed by Altonji, Elder, and Taber (2005) and Oster (2017), this paper shows that the observed correlations are unlikely to be driven by unobservables. Using a permutation test based on the structure of the language tree and the distribution of languages across countries, this paper demonstrate that the results are not driven by spurious correlations within language families. Gender languages appear to reduce women’s labor force participation and perpetuate support for unequal treatment of women.

That is from a new World Bank working paper by Pamela Jakiela and Owen Ozier, via the excellent Kevin Lewis.  Kevin also points us to a new study indicating that East Asians smile fifty percent less than Americans.

Simplifiers vs. constructors in science

Simplifiers give one a better overall picture of how the world works, whereas constructors are trying to build something.  The balance seems to be shifting, for instance in physics:

Within the Physics label…we find the simplifiers dominated three quarters of the Nobel Prizes from 1952 to 1981, but more recently constructors have edged the balance with more than half of those from 1982 to 2011.

There is also a shift toward constructors in chemistry, though it is less abrupt.  In the fields of physiology and medicine, however, simplifiers reign supreme and there has been no shift across time.  Three-quarters of the prizes are still going to simplifiers.

Does that mean we should be relatively bullish about progress in those areas, based on forthcoming fundamental breakthroughs?

All these points are from Jeremy J. Baumberg’s new and interesting The Secret Life of Science: How It Really Works and Why It Matters.

Teacher wages and upward mobility

From David Card, Ciprian Domnisoru, and Lowell Taylor, the last few sentences are the most interesting:

We use 1940 Census data to study the intergenerational transmission of human capital for children born in the 1920s and educated during an era of expanding but unequally  distributed public school resources. Looking at the gains in educational attainment between parents and children, we document lower average mobility rates for blacks than whites, but wide variation across states and counties for both races. We show that schooling choices of white children were highly responsive to the quality of local schools, with bigger effects for the children of less-educated parents. We then narrow our focus to black families in the South, where state-wide minimum teacher salary laws created sharp differences in teacher wages between adjacent counties. These differences had large impacts on schooling attainment, suggesting an important causal role for school quality in mediating upward mobility.

This result is not logically inconsistent with the signalling model, but I think it fits more readily into the human capital story.  If you think employers cannot easily distinguish between different qualities of worker (without the educational signal, that is), probably you also should think employers cannot distinguish among the quality of adjacent schools on the basis of what they pay their teachers in relative terms.  And in that case, the schools hiring the better teachers are probably increasing the productivity of their students.

For the pointer I thank the excellent Samir Varma.

The Long-run Effects of Teacher Collective Bargaining

By Michael Lovenheim and Alexander Willén:

Teacher collective bargaining is a highly debated feature of the education system in the US. This paper presents the first analysis of the effect of teacher collective bargaining laws on long-run labor market and educational attainment outcomes, exploiting the timing of passage of duty-tobargain laws across cohorts within states and across states over time. Using American Community Survey data linked to each respondent’s state of birth, we examine labor market outcomes and educational attainment for 35-49 year olds, separately by gender. We find robust evidence that exposure to teacher collective bargaining laws worsens the future labor market outcomes of men: in the first 10 years after passage of a duty-to-bargain law, male earnings decline by $2,134 (or 3.93%) per year and hours worked decrease by 0.42 hours per week. The earnings estimates for men indicate that teacher collective bargaining reduces earnings by $213.8 billion in the US annually. We also find evidence of lower male employment rates, which is driven by lower labor force participation. Exposure to collective bargaining laws leads to reductions in the skill levels of the occupations into which male workers sort as well. Effects are largest among black and Hispanic men. Estimates among women are often confounded by secular trend variation, though we do find suggestive evidence of negative impacts among nonwhite women. Using data from the 1979 National Longitudinal Survey of Youth, we demonstrate that collective bargaining laws lead to reductions in measured non-cognitive skills among young men.

Here is the NBER link, via Matt Yglesias.

Do better scientists smile more?

Theory and research indicates that individuals with more frequent positive emotions are better at attaining goals at work and in everyday life. In the current study we examined whether the expression of genuine positive emotions by scientists was positively correlated with work-related accomplishments, defined by bibliometric (e.g. number of citations) and sociometric (number of followers for scholarly updates) indices. Using a sample of 440 scientists from a social networking site for researchers, multiple raters coded smile intensity (full smile, partial smile, or no smile) in publicly available photographs. We found that scientists who presented a full smile had the same quantity of publications yet of higher quality (e.g. citations per paper) and attracted more followers to their updates compared to less positive emotionally expressive peers; results remained after controlling for age and sex. Thin-slicing approaches to the beneficial effects of positive emotionality offer an ecologically valid approach to complement experimental and longitudinal evidence. Evidence linking positive emotional expressions to scientific impact and social influence provides further support for broaden and build models of positive emotions.

I wonder for which fields this might not be true…?

The paper has many authors, including my colleague Todd B. Kashdan.  Via the excellent Kevin Lewis.

Trump understands this, perhaps you do not

Given the very negative baseline views that respondents have of immigrants, simply making them think about immigration in a randomized manner makes them support less redistribution, including actual donations to charities.

That is from research by Alesina, Miano, and Stantcheva.  And don’t forget this:

We also experimentally show respondents information about the true i) number, ii) origin, and iii) “hard work” of immigrants in their country. On its own, information on the “hard work” of immigrants generates more support for redistribution. However, if people are also prompted to think in detail about immigrants’ characteristics, then none of these favorable information treatments manages to counteract their negative priors that generate lower support for redistribution.

The still-coherent culture that is the United States

From Marianne Bertrand and Emir Kamenica at NBER:

The results overall refute the hypothesis of growing cultural divides.  With few exceptions, the extent of cultural distance has been broadly constant over time.

The data also show that:

1. From to 1995, the time use behavior of women and men converged a good deal, but not since then.

2. Differences in social attitudes by political ideology and income have increased since the 1970s.  The rich and the poor have diverged the most in terms of their attitudes toward law enforcement.

3. Whites and non-whites “have converged somewhat on social attitudes but have diverged in consumer behavior.”

4. “Nevertheless, our headline result is that for all other demographic divisions and cultural dimensions, cultural distance has been broadly constant over time.”  For instance, the media consumption gap between rich and poor has not been growing.

5. “The brand most predictive of top income in 1992 is Grey Poupon Dijon mustard. By 2004, the brand most indicative of the rich is Land O’Lakes butter, followed by Kikkoman soy sauce. By the end of the sample, ownership of Apple products (iPhone and iPad) tops the list. Knowing whether someone owns an iPad in 2016 allows us to guess correctly whether the person is in the top or bottom income quartile 69 percent of the time. Across all years in our data, no individual brand is as predictive of being high-income as owning an Apple iPhone in 2016.”

6. Voting and “trusting people” are among the “social attitudes” that best predict being rich.

7. Education is matched about as tightly to social attitudes now as it was in 1976.

8. “By 2016, watching Love It or List It and Property Brothers, both HGTV shows, were the most indicative of being educated.” [TC: yikes!]

9. Since the 1990s, there has been no divergence in the TV shows watched by liberals and conservatives.  Note that in 2001, the three TV shows that best predicted ideology were The Academy Awards, Will and Grace, and Friends, all liberal.  Nowadays it’s Fox shows, all conservative.

10. Liberals are more likely to drink alcohol, conservatives are more likely to go fishing.

11. Maybe this is the most important result: since 1976 there has not been much divergence between liberal and conservative attitudes toward civil liberties or law enforcement.  The divergence on government spending is noticeable but not enormous (see p.39).  the divergence on “Marriage, Sex, Abortion” is quite large.  In another words, the true polarization is happening across gender issues, as I’ve argued numerous times in the past.

12. Here are related important results on the cultural divide.  When will MSM articles catch up to the data?

How many places do you visit anyway?

The study, titled “Evidence for a conserved quantity in human mobility’ is published in Nature Human Behaviour is based on analyses of 40,000 people’s mobile traces collected in four different datasets.

It is also the first of its kind to investigate people’s mobility over time and study how their behavior changes.

Behind the project are Dr. Laura Alessandretti and Dr. Andrea Baronchelli, researchers in the Department of Mathematics at City, University of London, together with Professor Sune Lehmann from DTU Technical University of Denmark and the research team from Sony Mobile Communications.

“We first analysed the traces of about 1000 university students. The dataset showed that the students returned to a limited number of places, even though the places changed over time. I expected to see a difference in the behavior of students and a wide section of the population. But that was not the case. The result was the same when we scaled up the project to 40,000 people of different habits and gender from all over the world. It was not expected in advance. It came as a surprise,” says Dr. Alessandretti.

Old places disappear

The study showed that people are constantly exploring new places. They move to a new home, find a new favorite restaurant, find a new bar, or start going to another gym, etc. However, the number of regularly visited places is constantly 25 in a given period. If a new place is added to the list, one of the places disappears.

The pattern is the same when the researchers divide the locations into categories based on how often and how long time they spend at the location.

“People are constantly balancing their curiosity and laziness…

That is by John Stevenson, via K., here is the original research by Laura Andressetti  On this question I retain an open mind.

Ethnolinguistic favoritism in African politics

African political leaders have a tendency to favor members of their own ethnic group. Yet for all other ethnic groups in a country, it is unclear whether having a similar ethnicity to the leader is beneficial. To shed light on this issue, I use a continuous measure of linguistic similarity to quantify the ethnic similarity of a leader to all ethnic groups in a country. Combined with panel data on 163 ethnic groups partitioned across 35 sub-Saharan countries, I use within-group time variation in similarity that results from a partitioned group’s concurrent exposure to multiple national leaders. Findings show that ethnic favoritism is more widespread than previously believed: in addition to evidence of coethnic favoritism, I document evidence of non-coethnic favoritism that typically goes undetected in the absence of a continuous measure of similarity. I also find that patronage tends to be targeted toward ethnic regions rather than individuals of a particular ethnic group. I relate these results to the literature on coalition building, and provide evidence that ethnicity is one of the guiding principles behind high-level government appointments.

That is from Andrew Dickens in the latest American Economic Review.

The economics of land mines

Landmine contamination affects the lives of millions in many conflict-ridden countries long after the cessation of hostilities. Yet, little research exists on its impact on post-conflict recovery. In this study, we explore the economic consequences of landmine clearance in Mozambique, the only country that has moved from “heavily-contaminated” in 1992 to “mine-free” status in 2015. First, we compile a dataset detailing the evolution of clearance, collecting thousands of reports from the numerous demining actors. Second, we exploit the timing of demining to assess its impact on local economic activity, as reflected in satellite images of light density at night. The analysis reveals a moderate positive association that masks sizeable heterogeneity. Economic activity responds strongly to clearance of the transportation network, trade hubs, and more populous areas, while the demining-development association is weak in rural areas of low population density. Third, recognizing that landmine removal recon figured the accessibility to the transportation infrastructure, we apply a “market-access” approach to quantify both its direct and indirect effects. The market-access estimates reveal substantial improvements on aggregate economic activity. The market-access benefits of demining are also present in localities without any contamination. Fourth, counterfactual policy simulations project considerable gains had the fragmented process of clearance in Mozambique been centrally coordinated, prioritizing clearance of the colonial transportation routes.

That is a new NBER paper by Giorgio Chiovelli, Stelios Michalopoulos, and Elias  Papaioannou, via Dan Wang.  File under “Not Unrelated to NIMBY.”

Do liberals and conservatives shop differently?

I usually urge care in interpreting or even believing such results, but if you are game here is another entry into the sweepstakes:

In our research, conservatives tended to differentiate themselves through products that show that they are better than others – for example, by choosing products from high-status luxury brands. In contrast, liberals tended to differentiate themselves through products that show that they are unique from others – for example, by choosing products with unconventional designs or colors. These distinct preferences emerged across multiple studies in which U.S. participants (university students who completed surveys in the lab, adults who took surveys online, and members of a research panel) indicated their political ideology and made real or hypothetical choices between products.

In one study, participants chose between coffee mugs that would be customized with their names and the message “Just Better” or “Just Different.” Conservatives were 2.2 times more likely than liberals to choose the mug that signaled superiority (“Just Better”) over the one that signaled uniqueness (“Just Different”). In another study, participants could win a gift card from one of two brands as a reward for participation — Ralph Lauren, which based on our numerous pretests of consumers’ brand perceptions generally signals superiority, and Urban Outfitters, which based on our pretests generally signals uniqueness. Conservatives tended to prefer Ralph Lauren, whereas liberals tended to prefer Urban Outfitters.

That is from Nailya Ordabayeva.