Indeed, the study finds that many schools that receive relatively low ratings perform better than these ratings would imply. Conventional ratings, the research makes clear, are highly correlated with race. Specifically, many published school ratings are highly positively correlated with the share of the student body that is white.

“A school’s average outcomes reflect, to some extent, the demographic mix of the population it serves,” says MIT economist Josh Angrist, a Nobel Prize winner who has long analyzed education outcomes. Angrist is co-author of a newly published paper detailing the study’s results.

The study, which examines the Denver and New York City school districts, has the potential to significantly improve the way school quality is measured. Instead of raw aggregate measures like test scores, the study uses changes in test scores and a statistical adjustment for racial composition to compute more accurate measures of the causal effects that attending a particular school has on students’ learning gains. This methodologically sophisticated research builds on the fact that Denver and New York City both assign students to schools in ways that allow the researchers to mimic the conditions of a randomized trial.

In documenting a strong correlation between currently used rating systems and race, the study finds that white and Asian students tend to attend higher-rated schools, while Black and Hispanic students tend to be clustered at lower-rated schools.

“Simple measures of school quality, which are based on the average statistics for the school, are invariably highly correlated with race, and those measures tend to be a misleading guide of what you can expect by sending your child to that school,” Angrist says.

The paper, “Race and the Mismeasure of School Quality,” appears in the latest issue of the American Economic Review: Insights. The authors are Angrist, the Ford Professor of Economics at MIT; Peter Hull, a professor of economics at Brown University; Parag Pathak, the Class of 1922 Professor of Economics at MIT; and Christopher Walters PhD ’13, an associate professor of economics at the University of California at Berkeley. Angrist and Pathak are both professors in the MIT Department of Economics and co-founders of MIT’s Blueprint Labs, a research group that often examines school performance.

The study uses data provided by the Denver and New York City public school districts, where 6th-graders apply for seats at certain middle schools, and the districts use a school-assignment system. In these districts, students can opt for any school in the district, but some schools are oversubscribed. In these circumstances, the district uses a random lottery number to determine who gets a seat where.

By virtue of the lottery inside the seat-assignment algorithm, otherwise-similar sets of students randomly attend an array of different schools. This facilitates comparisons that reveal causal effects of school attendance on learning gains, as in a randomized clinical trial of the sort used in medical research. Using math and English test scores, the researchers evaluated student progress in Denver from the 2012-2013 through the 2018-2019 school years, and in New York City from the 2016-2017 through 2018-2019 school years.

Those school-assignment systems, it happens, are mechanisms some of the researchers have helped construct, allowing them to better grasp and measure the effects of school assignment.

“An unexpected dividend of our work designing Denver and New York City’s centralized choice systems is that we see how students are rationed from [distributed among] schools,” says Pathak. “This leads to a research design that can isolate cause and effect.”

Ultimately, the study shows that much of the school-to-school variation in raw aggregate test scores stems from the types of students at any given school. This is a case of what researchers call “selection bias.” In this case, selection bias arises from the fact that more-advantaged families tend to prefer the same sets of schools.

“The fundamental problem here is selection bias,” Angrist says. “In the case of schools, selection bias is very consequential and a big part of American life. A lot of decision-makers, whether they’re families or policymakers, are being misled by a kind of naïve interpretation of the data.”

Indeed, Pathak notes, the preponderance of more simplistic school ratings today (found on many popular websites) not only creates a deceptive picture of how much value schools add for students, but has a self-reinforcing effect — since well-prepared and better-off families bid up housing costs near highly-rated schools.As the scholars write in the paper, “Biased rating schemes direct households to low-minority rather than high-quality schools, while penalizing schools that improve achievement for disadvantaged groups.”

The research team hopes their study will lead districts to examine and improve the way they measure and report on school quality. To that end, Blueprint Labs is working with the New York City Department of Education to pilot a new ratings system later this year. They also plan additional work examining the way families respond to different sorts of information about school quality.

Given that the researchers are proposing to improve ratings in what they believe is a straightforward way, by accounting for student preparation and improvement, they think more officials and districts may be interested in updating their measurement practices.

“We’re hopeful that the simple regression adjustment we propose makes it relatively easy for school districts to use our measure in practice,” Pathak says.

The research received support from the Walton Foundation and the National Science Foundation.

‘People aren’t purely truth-seekers — many beliefs are influenced by emotions and driven by what is pleasant or comforting. Like belief in an afterlife or optimism about health outcomes,’ says Joël van der Weele, professor of Economic Psychology at the UvA. Working alongside professor of Neuroeconomics Jan Engelmann and an international team, Van der Weele set out to answer whether people become overly optimistic when facing potential hardships. ‘So far studies haven’t provided clear evidence for wishful thinking, with many not backing up the idea,’ explains Engelmann. ‘But these mainly focused on positive outcomes, like winning a lottery. We examined how both positive and negative outcomes influence biased beliefs.’

Choosing the most pleasant outcome

Understanding self-deception and its causes is difficult in real-world situations. The study involved a set of experiments with over 1,700 participants, conducted in a lab and online. Participants were briefly shown various patterns, such as sets of differently oriented stripes or coloured dots, and were asked what kind of pattern they saw. Some of these patterns were linked to a negative outcome to induce anxiety, either a mild and non-dangerous electrical shock (in the lab) or a loss of money (online). ‘We wanted to see if people make more mistakes in recognising patterns associated with a negative outcome, thinking it was actually a harmless pattern. That would indicate wishful thinking,’ explains Van der Weele.

The study consistently found that participants were less likely to correctly identify patterns associated with a shock or loss. ‘The participants tended to see a pattern that aligned with what was more desirable,’ Engelmann says. ‘Previous research looked at wishful thinking related to positive outcomes and found mixed results, with many studies not finding an effect. Our study demonstrates very clearly that the negative emotion of anxiety about an outcome leads to wishful thinking.’

Making people more realistic

The researchers also tested interventions designed to make people more realistic. The first involved making the patterns easier to recognise. ‘Reducing uncertainty did indeed turn out to reduce wishful thinking,’ says Van der Weele. The second intervention was to offer higher potential earnings for correct pattern recognition. This intervention had little effect, except when participants could gather more evidence about the exact pattern they were shown. ‘When people had more time to collect evidence and were better rewarded for a correct answer, they became more realistic,’ explains Engelmann.

Finally, in the experiments where negative outcomes were replaced by positive outcomes, participants showed no wishful thinking. According to the authors this shows that reducing negative emotions can lessen overoptimism.

Wishful thinking in the ‘real world’

The authors recognise that wishful thinking can be useful because it helps us deal with bad feelings and manage uncertainty. Engelmann: ‘Wishful thinking is important for humans in coping with anxiety about possible future events.’ For Van der Weele and Engelmann, the concern is situations in which too much optimism stops people from getting the information they need or from acting in a way that would benefit them. ‘People can get too hopeful when things are uncertain. We observe this happening with climate change, when financial markets fluctuate, and even in personal health situations when people avoid medical help because they think everything will be fine. We need to know more about when wishful thinking helps and when it hurts.’

Crimean-Congo haemorrhagic fever virus (CCHF virus) is spread through tick bites and can cause haemorrhagic fever. The disease is serious and has a mortality rate of up to 40 per cent depending on the health status of the person infected. Common symptoms include fever, muscle pain, abdominal pain, joint pain, vomiting and haemorrhaging that can cause organ failure.

The disease has spread to Europe

The virus is present in around 40 countries, including Central Asia, the Middle East and parts of Africa. In recent years, the disease has spread to new geographical areas as a result of climate change, including Spain and France. The tick species that can spread the disease has also been observed in Germany and Sweden. There are currently no effective treatments for the disease.

In a new study, researchers at Karolinska Institutet in Sweden and others have found that the virus enters our cells via a protein on the cell surface, the so-called LDL receptors that regulate blood cholesterol levels.

To identify the protein, the researchers used human mini-organs grown in test tubes and an advanced stem cell library from JLP Health. The same platform has previously been used to identify how the Ebola virus enters cells.

The results were also confirmed in tests on mice, which showed that mice lacking the LDL receptor did not get as sick as others.

Researchers want to trick the virus

The discovery is an important step towards developing drugs for Crimean-Congo haemorrhagic fever, according to Ali Mirazimi, adjunct professor at the Department of Laboratory Medicine, Karolinska Institutet, and one of the researchers behind the study.

“Once we know which receptor the virus uses, we can produce the receptor in test tubes and administer it as a drug,” he says. “Then we can trick the virus into binding to those receptors instead of to the cells and thus stop the virus from spreading in our bodies.”

This knowledge is essential if the disease were to become more common and spread to new areas. Normally it takes many years to develop a drug, but the COVID-19 pandemic and the development of the SARS-CoV-2 vaccine showed that it can be done much faster if everyone decides it is a priority.

Ticks are spread by migratory birds

“This is an important step in our preparedness for the disease,” says Ali Mirazimi. “Crimean-Congo haemorrhagic fever is a disease we would rather not have. The ticks are spread by migratory birds and have already been found in Sweden. If the disease starts appearing in more places, we may already have a drug that we can take into clinical trials.”

The research was conducted in collaboration with the Medical University of Vienna, Austria, Helmholtz Centre for Infection Research, Germany, the National Institutes of Health, USA, and the company JLP Health. It was financed mainly by the Swedish Research Council and the EU. No conflicts of interest have been reported.

Through DNA sequencing of the animals and their tumors, University of South Florida Assistant Professor of Integrative Biology Mark Margres and doctoral student Dylan Gallinson have tracked the genomic interactions between the devils and the cancer. Their findings are published in a coauthored paper, “Intergenomic signatures of coevolution between Tasmanian devils and an infectious cancer,” in the Proceedings of the National Academy of Sciences.

“A big question in biology is the genetic basis for disease. The classic way to determine this is through genome studies and regression analysis that matches genes with disease risk,” Margres said. “Previously there hadn’t been a technique to study the interactions between both genomes.”

Using a recently developed joint genome-wide association study, Margres and Gallinson assessed 960 genomes and 15 years of data on captured devils to track the co-evolution of the devils and the cancer.

“Our collaborators in Tasmania have been monitoring the spread of the disease and collecting tissue samples,” Gallinson said. “We sequenced the DNA of both the tumors and the devils to find the mutation that contributes to the manifestation of the disease.”

Their findings can inform both epidemiological models that track infectious diseases and devil management strategies that focus on saving the endangered species.

The process of spins lining up, however, does not happen all at once. Rather, when the magnetic field is applied, different regions, or so-called domains, influence others nearby, and the changes spread across the material in a clumpy fashion. Scientists often compare this effect to an avalanche of snow, where one small lump of snow starts falling, pushing on other nearby lumps, until the entire mountainside of snow is tumbling down in the same direction.

This avalanche effect was first demonstrated in magnets by the physicist Heinrich Barkhausen in 1919. By wrapping a coil around a magnetic material and attaching it to a loudspeaker, he showed that these jumps in magnetism can be heard as a crackling sound, known today as Barkhausen noise.

Now, reporting in the journal Proceedings of the National Academy of Sciences (PNAS), Caltech researchers have shown that Barkhausen noise can be produced not only through traditional, or classical means, but through quantum mechanical effects. This is the first time quantum Barkhausen noise has been detected experimentally. The research represents an advance in fundamental physics and could one day have applications in creating quantum sensors and other electronic devices.

“Barkhausen noise is the collection of the little magnets flipping in groups,” says Christopher Simon, lead author of the paper and a postdoctoral scholar in the lab of Thomas F. Rosenbaum, a professor of physics at Caltech, the president of the Institute, and the Sonja and William Davidow Presidential Chair. “We are doing the same experiment that has been done many times, but we are doing it in a quantum material. We are seeing that the quantum effects can lead to macroscopic changes.”

Usually, these magnetic flips occur classically, through thermal activation, where the particles need to temporarily gain enough energy to jump over an energy barrier. However, the new study shows that these flips can also occur quantum mechanically through a process called quantum tunneling.

In tunneling, particles can jump to the other side of an energy barrier without having to actually pass over the barrier. If one could scale up this effect to everyday objects like golf balls, it would be like the golf ball passing straight through a hill rather than having to climb up over it to get to the other side.

“In the quantum world, the ball doesn’t have to go over a hill because the ball, or rather the particle, is actually a wave, and some of it is already on the other side of the hill,” says Simon.

In addition to quantum tunneling, the new research shows a co-tunneling effect, in which groups of tunneling electrons are communicating with each other to drive the electron spins to flip in the same direction.

“Classically, each one of the mini avalanches, where groups of spins flip, would happen on its own,” says co-author Daniel Silevitch, research professor of physics at Caltech. “But we found that through quantum tunneling, two avalanches happen in sync with each other. This is a result of two large ensembles of electrons talking to each other and, through their interactions, they make these changes. This co-tunneling effect was a surprise.”

For their experiments, members of the team used a pink crystalline material called lithium holmium yttrium fluoride cooled to temperatures near absolute zero (equivalent to minus 273.15 degrees Celsius). They wrapped a coil around it, applied a magnetic field, and then measured brief jumps in voltage, not unlike what Barkhausen did in 1919 in his more simplified experiment. The observed voltage spikes indicate when groups of electron spins flip their magnetic orientations. As the groups of spins flip, one after the other, a series of voltage spikes is observed, i.e. the Barkhausen noise.

By analyzing this noise, the researchers were able to show that a magnetic avalanche was taking place even without the presence of classical effects. Specifically, they showed that these effects were insensitive to changes in the temperature of the material. This and other analytical steps led them to conclude that quantum effects were responsible for the sweeping changes.

According to the scientists, these flipping regions can contain up to 1 million billion spins, in comparison to the entire crystal that contains approximately 1 billion trillion spins.

“We are seeing this quantum behavior in materials with up to trillions of spins. Ensembles of microscopic objects are all behaving coherently,” Rosenbaum says. “This work represents the focus of our lab: to isolate quantum mechanical effects where we can quantitively understand what is going on.”

Another recent PNAS paper from Rosenbaum’s lab similarly looks at how tiny quantum effects can lead to larger-scale changes. In this earlier study, the researchers studied the element chromium and showed that two different types of charge modulation (involving the ions in one case and the electrons in the other) operating at different length scales can interfere quantum mechanically. “People have studied chromium for a long time,” says Rosenbaum, “but it took until now to appreciate this aspect of the quantum mechanics. It is another example of engineering simple systems to reveal quantum behavior that we can study on the macroscopic scale.”

The PNAS study titled “Quantum Barkhausen noise induced by domain wall cotunneling” was funded by the U.S. Department of Energy and the National Sciences and Engineering Research Council of Canada. The author list also includes Philip Stamp, a visiting associate in physics at Caltech and a physics professor at University of British Columbia.

Located predominantly in cold regions at high latitude, boreal forests are estimated to store nearly 30 percent of the world’s soil carbon, making them the world’s largest reservoir of land-based carbon. This stored carbon is found mostly in the forests’ humus layer, which contains decomposed leaves and other organic matter.

A global, long-term study led by Duke University researchers has found that higher levels of manganese in this layer stimulated decomposition of soil organic matter, and released more carbon dioxide than did those forest plots with less or no manganese. The work appeared March 19 in the Proceedings of the National Academy of Sciences (PNAS).

“Conventional wisdom is these forests are like a global vault of carbon, where carbon is put into the vault versus taken out,” said William H. Schlesinger, professor emeritus at Duke University’s Nicholas School of the Environment and study co-author. “These findings reveal a crack in the vault, where enough manganese over time stimulates the release of carbon dioxide into the atmosphere, which has implications for climate mitigation efforts and the global carbon cycle,” said Schlesinger.

Certain industrial processes, such as metal smelting or combustion of manganese-containing fuels, can release airborne manganese which is later deposited in soils downwind.

This is one of many human activities, such as the burning of fossil fuels, deforestation, and land-use changes, that have disturbed the natural carbon cycle, leading to an increase in atmospheric carbon dioxide concentrations that contribute to global warming and climate change.

“Carbon inventorying is still an evolving science,” said Yunyu Zhang, lead author and graduate student from the Chinese Academy of Sciences. “It is essential to figure out which factors regulate this huge carbon pool [in boreal forests’ soil], especially given continuous… industrialization.”

Researchers analyzed data from boreal forests worldwide, and fertilized soil with manganese over 14 years (2009-2023) in China’s Daxing’an Mountains. Results showed the level of exchangeable manganese — the part of manganese that plants can use as nutrients — determined how much carbon was stored in boreal forest soil. After four years, carbon storage on plots fertilized with manganese fell by nearly 13 percent, meaning more carbon was released into the atmosphere.

“To develop effective and sustainable strategies, it is critical to understand complex interactions between trace nutrients and carbon storage,” Zhang said. “It is even more important to predict how those interactions work in the long term, considering the impact of human activities.”

Schlesinger emphasized the need for further research and action, noting how the study’s findings highlight the importance of soil nutrient dynamics, such as the level of exchangeable manganese, in climate change mitigation efforts.

He urged further study of the role of manganese not only in soil, but also in the air, on land-based carbon emissions, the boreal forest ecosystem, and climate mitigation.

“There’s no proverbial foolproof vault or absolute forest sink,” Schlesinger said. “We need integrated approaches to land management and climate mitigation. Climate has traditionally been considered a major factor in carbon storage, but we now see how manganese is also a key indicator, something that has long been overlooked and underexamined.”

The National Natural Science Foundation of China and Chinese Academy of Sciences co-funded the study.