Category: Data Source
We analyze a large-scale field experiment conducted on a US search engine in which 3.3 million users were randomized into seeing more, or less advertising. Our data rejects that users are, overall, averse to search advertising targeted to them. At the margin, users prefer the search engine with higher level of advertising. The usage of the search engine (in terms of number of searches, and number of search sessions) is higher among users who see higher levels of advertising, relative to the control group. This difference in usage persists even after the experimental treatment ends. The increase in usage is higher for users on the margin who, in the past, typed a competing search engine’s name in the search query and navigated away from our focal search engine. On the supply side, higher level of advertising increases traffic to newer websites. Consumer response to search advertising is also more positive when more businesses located in the consumer’s state create new websites. Quantitatively, the experimental treatment of a higher level of advertising increases ad clicks which leads to between 4.3% to 14.6% increase in search engine revenue.
Overall, patterns in our data are consistent with an equilibrium in which advertising conveys relevant “local” information, which is unknown to the search engine, and therefore missed by the organic listings algorithm. Hence, search advertising makes consumers better off on average. On the margin, the search engine does not face a trade-off between advertising revenue and search engine usage.
Nationwide’s pet health insurance division has partnered with Purdue University researchers to track trends in pet insurance payouts. The researchers track a “basket” of the most commonly-utilized procedures to see how the typical veterinary visit has changed in price over time. According to their research, these ordinary expenses declined by 6 percent from January 2009 to December 2017 after adjusting for inflation.
This decrease is corroborated by less reliable sources, such as the American Pet Products Association (APPA) annual consumer spending surveys. For virtually every year tracked (accessible via web archive), cat and dog owners reported spending less money on average routine and surgical visits. The data is jumpier than the Nationwide and Purdue rigorous analysis of 30 million insurance claims but confirms an interesting – and counterintuitive – trend. In a system where consumers and patients’ “representatives” have enough skin in the game, healthcare prices behave like they would in most other markets.
That is from Ross Marchand, “Why cats pay a lower price for CAT scans.” Here is earlier work by Einav, Finkelstein, and Gupta about pet health care being about as inefficient as human health care. I don’t consider this a settled issue, but it is interesting to hear a revision on what had been the most common take.
The Socioeconomic High-resolution Rural-Urban Geographic Platform for India (SHRUG) is a geographic platform that facilitates data sharing between researchers working on India. It is an open access repository currently comprising dozens of datasets covering India’s 500,000 villages and 8000 towns using a set of a common geographic identifiers that span 25 years.
That is the topic of a new paper by Mohsen Javdani and Ha-Joon Chang, here is part of the abstract:
Using an online randomized controlled experiment involving economists in 19 countries, we examine the effect of ideological bias on views among economists. Participants were asked to evaluate statements from prominent economists on different topics, while source attribution for each statement was randomized without participants’ knowledge. For each statement, participants either received a mainstream source, an ideologically different less-/non-mainstream source, or no source. We find that changing source attributions from mainstream to less-/non-mainstream, or removing them, significantly reduces economists’ reported agreement with statements. This contradicts the image economists have of themselves…
And from the paper:
Consistent with our overall findings, we find that for all but three statements, changing source attributions to a less/non-mainstream source significantly reduces the agreement level. The estimated reductions range from around one-tenth of a standard deviation to around half of a standard deviation.
The largest agreement reduction is for this sentence:
“Economic discourse of any sort — verbal, mathematical, econometric — is rhetoric; that is, an effort to persuade.”
You also can test which kinds of authority reassignation alter the level of agreement. And thus:
We find that the estimated ideological bias among female economists is around 40 percent less than their male counterparts.
The countries where economists exhibit the highest ideological bias are Ireland, Japan, Australia, and Scandinavia, where for Austria, Brazil, and Italy the ideological bias is smallest. South Africa, France, and Italy are most conformist to mainstream opinion.
It is a wordy and poorly written paper, and they don’t consider the possibility that deference to authority perhaps is the rational Bayesian move, not the contrary. Still, it has numerous results of interest. Here is the authors’ blog post on the paper.
It seems so, at least in Republican-controlled states:
There have been dozens of high-profile mass shootings in recent decades. This paper presents three main findings about the impact of mass shootings on gun policy. First, mass shootings evoke large policy responses. A single mass shooting leads to a 15% increase in the number of firearm bills introduced within a state in the year after a mass shooting. This effect increases with the extent of media coverage. Second, mass shootings account for a small portion of all gun deaths, but have an outsized influence relative to other homicides. Third, when looking at bills that were actually enacted into law, the impact of mass shootings depends on the party in power. The annual number of laws that loosen gun restrictions doubles in the year following a mass shooting in states with Republican-controlled legislatures. We find no significant effect of mass shootings on laws enacted when there is a Democrat-controlled legislature, nor do we find a significant effect of mass shootings on the enactment of laws that tighten gun restrictions.
That is the abstract of a new NBER working paper by Michael Luca, Deepak Malhotra, and Christopher Poliquin.
Evidence of a widening gulf has become too copious to ignore. Last month, for example, a poll by the Allensbach Institute asked eastern Germans whether they saw democracy as practised in Germany as the best form of government. Only 31 per cent agreed. Two years ago, the figure was 53 per cent.
In western Germany, meanwhile, 72 per cent described democracy as the best form of government, broadly unchanged from two decades ago.
The same divergence shows up when Germans in both parts of the country are asked about their identity: 47 per cent of eastern Germans say they identify above all as eastern Germans, compared with only 44 per cent who feel simply German. This, too, is a sharp reversal from only a few years ago.
Also striking is the sheer persistence of specifically eastern German views and stereotypes: even 30 years after the fall of the wall (and with an east German chancellor, Angela Merkel, holding office since 2005), more than a third of eastern Germans describe themselves as “second-class citizens”.
That is from Tobias Buck in the FT.
>We estimate the size of US consumer gains from Chinese imports during 2004–2015. Using barcode-level price and expenditure data, we construct inflation rates under CES preferences, and use Chinese exports to Europe as an instrument. We find significant negative effects of Chinese imports on US prices. This effect is driven by both changes in the prices of existing goods and the entry of new goods, and it is similar across consumer groups by income or region. A simple benchmarking exercise suggests that Chinese imports led to a 0.19 percentage point annual reduction in the price index for consumer tradables.
That is from AER Insights by Liang Bai and Sebastian Stumpner. I would have expected a somewhat higher magnitude, and perhaps this in part explains why the trade war has been proceeding.
Team impact is predicted more by the lower-citation rather than the higher-citation team members, typically centering near the harmonic average of the individual citation indices. Consistent with this finding, teams tend to assemble among individuals with similar citation impact in all fields of science and patenting. In assessing individuals, our index, which accounts for each coauthor, is shown to have substantial advantages over existing measures. First, it more accurately predicts out-of-sample paper and patent outcomes. Second, it more accurately characterizes which scholars are elected to the National Academy of Sciences. Overall, the methodology uncovers universal regularities that inform team organization while also providing a tool for individual evaluation in the team production era.
That is part of the abstract of a new paper by Mohammad Ahmadpoor and Benjamin F. Jones.
…an additional dispensary in a neighborhood leads to a reduction of 17 crimes per month per 10,000 residents, which corresponds to roughly a 19 percent decline relative to the average crime rate over the sample period. Reductions in crime are highly localized, with no evidence of spillover benefits to adjacent neighborhoods.
That is from a newly published paper by Jeffrey Brinkman and David Mok-Lamme, via the excellent Kevin Lewis.
The number of people living in the Paris departement, or administrative area, dropped by an average of 11,900 people a year between 2011 and 2016, the most recent figures available, according to the national statistics agency. Paris’s urbanism institute, Apur, forecasts that the decline of the inner city population will continue for about another six years.
It is a sharp contrast with the urban renaissance that has taken place in many of the world’s major cities over the past 20 years, but Paris is not alone.
New York City shed a net 39,500 people in 2018 and 37,700 the year before, reversing the previous upward trend.
In London, the population is still growing, bolstered by births and international immigration; but when it comes to internal migration, the net movement of people out of the UK city totalled more than 100,000 in the year to June 2018.
Correlation ain’t causality, and yet…
Via Matthew C. Klein.
Are there systematic trends around the world in levels of creativity, aggressiveness, life satisfaction, individualism, trust, and suicidality? This article suggests a new field, latitudinal psychology, that delineates differences in such culturally shared features along northern and southern rather than eastern and western locations. In addition to geographical, ecological, and other explanations, we offer three metric foundations of latitudinal variations: replicability (latitudinal gradient repeatability across hemispheres), reversibility (north-south gradient reversal near the equator), and gradient strength (degree of replicability and reversibility). We show that aggressiveness decreases whereas creativity, life satisfaction, and individualism increase as one moves closer to either the North or South Pole. We also discuss the replicability, reversibility, and gradient strength of (a) temperatures and rainfall as remote predictors and (b) pathogen prevalence, national wealth, population density, and income inequality as more proximate predictors of latitudinal gradients in human functioning. Preliminary analyses suggest that cultural and psychological diversity often need to be partially understood in terms of latitudinal variations in integrated exposure to climate-induced demands and wealth-based resources. We conclude with broader implications, emphasizing the importance of north-south replications in samples that are not from Western, educated, industrialized, rich, and democratic (WEIRD) societies.
Here is the article, via several MR readers.
The subtitle of the paper is: “Evidence from Over 250,000 Projects and 2.5 Million Wage Bill Proposals” and here is the abstract:
We explore whether there is a gender wage gap in one of the largest EU online labor markets, PeoplePerHour. Our unique dataset consists of 257,111 digitally tradeable tasks of 55,824 hiring employers from 188 countries and 65,010 workers from 173 countries that made more than 2.5 million wage bill proposals in the competition for contracts. Our data allows us to track the complete hiring process from the employers’ design of proposed contracts to the competition among workers and the final agreement between employers and successful candidates. Using Heckman and OLS estimation methods we provide empirical evidence for a statistically significant 4% gender wage gap among workers, at the project level. We also find that female workers propose lower wage bills and are more likely to win the competition for contracts. Once we include workers’ wage bill proposals in the regressions, the gender wage gap virtually disappears, i.e., it is statistically insignificant and very small in magnitude (0.3%). Our results also suggest that female workers’ higher winning probabilities associated with lower wage bill proposals lead to higher expected revenues overall. We provide empirical evidence for heterogeneity of the gender wage gap in some of the job categories, all job difficulty levels and some of the worker countries. Finally, for some subsamples we find a statistically significant but very small “reverse” gender wage gap.
Here is the paper by Estrella Gomez Herra and Frank Mueller-Langer, via Luke Froeb.
I don’t believe this result, from David S. Yeager, et.al., but I put it out for your consideration, just published in Nature and receiving much attention:
A global priority for the behavioural sciences is to develop cost-effective, scalable interventions that could improve the academic outcomes of adolescents at a population level, but no such interventions have so far been evaluated in a population-generalizable sample. Here we show that a short (less than one hour), online growth mindset intervention—which teaches that intellectual abilities can be developed—improved grades among lower-achieving students and increased overall enrollment to advanced mathematics courses in a nationally representative sample of students in secondary education in the United States. Notably, the study identified school contexts that sustained the effects of the growth mindset intervention: the intervention changed grades when peer norms aligned with the messages of the intervention. Confidence in the conclusions of this study comes from independent data collection and processing, pre-registration of analyses, and corroboration of results by a blinded Bayesian analysis.
Big if true, as they say. Via many of you, thanks.
Addendum: Alex covered this as a working paper last year with more details.
“A 2015 study of self-checkouts with handheld scanners, conducted by criminologists at the University of Leicester, also found evidence of widespread theft. After auditing 1 million self-checkout transactions over the course of a year, totaling $21 million in sales, they found that nearly $850,000 worth of goods left the store without being scanned and paid for. The Leicester researchers concluded that the ease of theft is likely inspiring people who might not otherwise steal to do so…. As one retail employee told the researchers, ‘People who traditionally don’t intend to steal [might realize that] … when I buy 20, I can get five for free.’