Wednesday, April 03, 2024

Majority of people with heart disease consume too much sodium


Study finds patients on average consume more than twice the recommended daily amount of sodium with little variation across socioeconomic groups



AMERICAN COLLEGE OF CARDIOLOGY





Individuals with heart disease stand to gain the most from a low-sodium diet but, on average, consume over twice the recommended daily sodium intake, according to a study being presented at the American College of Cardiology’s Annual Scientific Session.

Sodium is an essential nutrient, but consuming too much can raise blood pressure, which damages blood vessels and forces the heart to work harder. Excess sodium can also cause the body to retain fluid, exacerbating conditions like heart failure. The current U.S. Dietary Guidelines put out by the U.S. Department of Agriculture recommends most adults limit their sodium intake to less than 2,300 mg/day, which is equivalent to about 1 teaspoon of table salt. For individuals with cardiovascular diseases, the limit is even lower at 1,500 mg/day, according to guideline recommendations from the ACC and the American Heart Association.

This new study found that among a sample of more than 3,100 people with heart disease, 89% consumed more than the recommended daily maximum of 1,500 mg of sodium and, on average, study participants consumed more than twice this amount. Limiting sodium intake is a fundamental lifestyle modification shown to reduce the likelihood of subsequent major adverse cardiovascular events, researchers said. Their findings underscore the challenges many people face in keeping within recommended sodium limits, regardless of other factors such as socioeconomic status.

“Estimating sodium quantities in a meal can be challenging,” said Elsie Kodjoe, MD, MPH, an internal medicine resident at Piedmont Athens Regional Hospital in Athens, Georgia and the study’s lead author. “Food labels aid in dietary sodium estimation by providing sodium quantities in packaged food. Yet, adhering to a low sodium diet remains challenging even for individuals with cardiovascular disease who have a strong incentive to adhere.”

The study used data from patients diagnosed with a heart attack, stroke, heart failure, coronary artery disease or angina who participated in the National Health and Nutrition Examination Survey (NHANES) between 2009–2018.

Researchers estimated sodium intake based on questionnaires in which participants were asked to report everything they had consumed in 24 hours. According to the results, study participants with cardiovascular disease consumed an average of 3,096 mg of sodium per day, which is slightly lower than the national average of 3,400 mg/day reported by the U.S. Centers for Disease Control and Prevention.

“The relatively small difference in sodium intake suggests that people with cardiovascular disease are not limiting their intake very much compared with the general population and are also consuming more than double what is recommended,” Kodjoe said. “To make it easier for patients to adhere to dietary guidelines, we need to find more practical ways for the general public to estimate dietary sodium levels or perhaps consider a reduction in the sodium content of the food we consume right from the source.”

The researchers also compared sodium intake among people in different socioeconomic groups, but they did not find any significant differences between wealthier and less affluent participants after accounting for age, sex, race and educational attainment.

Individuals can take proactive measures to lower their sodium intake, Kodjoe said. This includes preparing more meals at home where they have greater control over the sodium content and paying close attention to food labels, particularly targeting foods with sodium levels of 140 mg or less per serving. Researchers suggested that better education around the benefits of limiting sodium could also help motivate more people to follow the recommendations.

“Cardiovascular disease is real, and it is the number one cause of morbidity and mortality worldwide according to the World Health Organization,” Kodjoe said. “Adhering to sodium guidelines is one of the easier strategies individuals could readily adopt to reduce hospitalizations, health care costs, morbidity and mortality associated with cardiovascular disease.”

One limitation of the study is that sodium intake was estimated based on food recall questionnaires, rather than 24-hour urine sodium measurements, which is considered the gold standard method. NHANES has included 24-hour urine sodium measurements in its data gathering methods in recent survey cycles, so future studies using this data could provide a more accurate assessment of sodium intake among people with cardiovascular disease.  

For more information on reducing sodium, visit CardioSmart.org/Sodium.

Kodjoe will present the study, “The Impact of Income to Poverty Ratio on Sodium Intake Among Adults with Cardiovascular Disease,” on Sunday, April 7, 2024, at 3:15 p.m. ET / 19:15 UTC in Hall B4-5.

ACC.24 will take place April 6-8, 2024, in Atlanta, bringing together cardiologists and cardiovascular specialists from around the world to share the newest discoveries in treatment and prevention. Follow @ACCinTouch@ACCMediaCenter and #ACC24 for the latest news from the meeting.


Want to cut US heart risks? Get more people into primary care, study suggests


Most care to address the “Essential Eight” risk factors for heart disease and stroke happens in general-care settings, but many with high risk don’t go



MICHIGAN MEDICINE - UNIVERSITY OF MICHIGAN





When someone has a heart attack or a stroke, specialized care can give them the best chance of surviving.

But when it comes to preventing those problems in the first place, most essential care happens in general primary care clinics, a new study suggests. Or it doesn’t happen at all, if someone can’t, won’t or doesn’t take the time to see a primary care doctor or nurse practitioner.

The study finds that a majority of people with any of these key measures for improving and maintaining cardiovascular health, and the majority of those taking medication to control four of those measures, saw only a primary care clinician in the past year, compared with those who saw a cardiologist alone or in addition to seeing a primary care provider.

The study focuses on seven of what the American Heart Association calls “Life’s Essential Eight” controllable risk factors for cardiovascular disease: high cholesterol, high blood pressure, diabetes, very high body mass index, tobacco use, low exercise and sleep problems such as insomnia. The data source used in the study doesn’t include information about the eighth risk factor, healthy food intake.

The study also finds that large percentages of people with these major cardiovascular risk factors didn’t see either type of health care provider in the past year, even if they said they were taking medications to control their blood pressure, cholesterol, blood sugar or stop smoking.

More than 50% of all tobacco users, 44% of those who say they have low levels of physical activity, and 38% of those with severe obesity said they hadn’t seen a primary care provider or cardiologist in the last year. Even among those taking medication to control cardiovascular risk factors, 15% to 20% said they hadn’t seen any provider in the past year.

The study is published in Circulation: Quality and Outcomes by a team from Michigan Medicine, the University of Michigan’s academic medical center, OhioHealth, and Weill Cornell Medicine.

 They used data from more than 66,000 adults interviewed in-depth about their health and health care in the last year, through the nationally representative Medical Expenditure Panel Survey conducted by the federal government.

Lead author Jeremy Sussman, M.D., M.Sc., and co-author Madeline Sterling, M.D., M.P.H., serve on the American Heart Association’s Primary Care Science Committee, which is working on a report on the role of primary care in cardiovascular health.

“As a society we need to recognize that preventing common conditions requires providers who can see patients often, and see the whole patient, which is the role of primary care,” said Sussman, a general internist and associate professor in the U-M Department of Internal Medicine. “While cardiovascular care guidelines are often written by specialists and subspecialists, this study shows that access to primary care is crucial to preventing or delaying some of the most common causes of death in the nation.”

The current crisis in access to primary care for American adults does not bode well for making inroads on the “Essential Eight,” Sussman notes. That crisis is caused by both a shortage of, and uneven distribution of, physicians, nurse practitioners and physician assistants who choose to practice general internal medicine, family medicine and geriatrics.

Long waits for appointments, and inability to find a provider who is accepting new patients, could delay identification and management of cardiovascular risk factors, including starting new preventive medications or adjusting doses to control risk factors appropriately.

People who should make sure to see a primary care provider at least once a year – even just via a telehealth appointment – include those who have already been prescribed an antihypertensive medication to bring down high blood pressure, a diabetes drug to bring down blood sugar, a statin to control cholesterol or a prescription quit-smoking medication.

Regular checkups can help ensure they’re getting the most preventive power out of these medicines.

But even if they’re not taking medication, most adults with at least one cardiovascular risk factor on the “Essential Eight” list should be seeing a primary care provider regularly, Sussman said.

“Primary care providers today can manage high blood pressure, high cholesterol, most cases of diabetes, and tobacco cessation without having to refer to a specialist, though of course specialists play a key role in more complex prevention cases and post-incident care,” he said. “They can also be important entry routes to nutrition counseling, weight management and exercise programs, and sleep disorders diagnosis and treatment.”

Policy measures to enhance access to primary care by training more providers and incentivizing them to practice in shortage areas, and efforts to support primary care providers in managing cardiovascular risk factors, will be important, the authors say. But in the immediate timeframe, they urge individuals with any of these risk factors to request an appointment with their clinic or seek one out if they don’t have a regular primary care provider.

In addition to Sussman and Sterling, who is a general internist and researcher at Weill Cornell, the study team includes author Michael Johansen, M.D., a family medicine physician with OhioHealth who trained at U-M.

Sussman is a member of the U-M Institute for Healthcare Policy and Innovation, the VA Center for Clinical Management Research, and the Division of General Medicine.

The AHA committee that Sussman and Sterling serve on is a joint subcommittee of the Council on Quality of Care and Outcomes Research, and the Council on Cardiovascular and Stroke Nursing.

Clinical Care for Life’s Essential 8 by Medical Specialty in the United States, an Observational Cohort Study, Circulation: Cardiovascular Quality and Outcomes, DOI:10.1161/CIRCOUTCOMES.123.010498  https://www.ahajournals.org/doi/10.1161/CIRCOUTCOMES.123.010498

 

The role of pollinators in the evolution of flowers with various sexual forms


Scientists have shown that Darwin’s theories of precise pollination in heterostylous plants hold true on a large scale


Peer-Reviewed Publication

UNIVERSITY OF SEVILLE





Researchers Violeta Simón, Marcial Escudero and Juan Arroyo, from the Department of Botany at the Faculty of Biology of the University of Seville, led a study in which, in collaboration with researchers from four other countries, they demonstrate Darwin’s hypothesis of precise pollination across all angiosperms (flowering plants).

In heterostylous species there are two (sometimes three) types of flowers, called morphs, which differ according to the location of their sexual organs. The L-morph has the stigma (female sex organs) higher and the anthers (male sex organs) below. And in the S-morph they are the other way around. Darwin proposed that this system evolved to promote cross-pollination (between different individuals, to increase the vigour of their progeny) through a mechanism of precise pollination between the male and female sex organs of each morph, on different parts of the pollinator’s body.

This hypothesis of precise pollination hinges on the presence of floral traits and pollinators that fit together like a jigsaw puzzle, so that pollen is accurately deposited and transferred.

“We conducted a comprehensive review of the presence of heterostyly in all angiosperm genera and found many more cases than had been reported in recent literature reviews on the subject. We then collected more than 10,000 data about floral morphology and pollinators across many heterostylous and non-heterostylous species, and placed these data into a mega-phylogeny of all angiosperms to find whether the evolution of heterostyly is associated with floral traits and pollinators that promote precise pollination,” explains researcher Violeta Simón.

By looking at the correlations between heterostyly, floral traits and pollinators, the researchers found that heterostyly does indeed evolve in flower lineages with a narrow floral tube and long proboscis pollinators such as butterflies and moths. These pieces fit together to allow pollen to be transferred precisely from one morph to another, as Darwin predicted.

“Heterostyly has been used as a model for studies of floral evolution since Darwin’s time, but such an ambitious study on a macroevolutionary scale has never before been undertaken. We believe it will be a seminal work for many researchers in this field,” says the researcher Simón. It is worth stressing that this research group has been studying this plant reproductive mechanism for almost 30 years, and is a leader in the role of ecology in its evolution.

This project received funding from the European Union’s Horizon 2020 research and innovation programme under the agreement 897890, grant PID2021-122715NB-I00 DiversiChrom funded by MCIN/AEI/ and by “ERDF A way of making Europe”.

 

 

 

Lung cancer does not decrease in line with reduced smoking




UMEA UNIVERSITY

Bengt Järvholm 

IMAGE: 

BENGT JÄRVHOLM, PROFESSOR AT DEPARTMENT OF PUBLIC HEALTH AND CLINICAL MEDICINE, UMEÅ UNIVERSITY, SWEDEN

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CREDIT: MATTIAS PETTERSSON




Despite the fact that the number of people who smoke has decreased very sharply in Sweden, the number of cases of lung cancer in the population is not decreasing as much as expected. Among women lung cancer has in fact increased. This is shown in a new study at Umeå University, Sweden. The study means that the view of how long smoking affects health may change.

“Smoking is undoubtedly the most important risk factor for lung cancer. It is therefore surprising that the decline in smoking is not yet more visible in the statistics. More research is needed to find out why this is the case,” says Bengt Järvholm, professor at the Department of Public Health and Clinical Medicine at UmeÃ¥ University.

The number of people who smoke has been declining in Sweden for many years. Today, one of twenty Swedes, about five percent, among men and women state that they smoke daily. In the 1960s, about one in two Swedish men between the ages of 18 and 69 smoked. Women generally started smoking later in history than men. In a large study in 1963, only slightly more than one in ten women, 11 per cent, aged 50–69 smoked, while 46 per cent of men were smokers. Among women, it was mainly younger people who smoked in the 1960s.

According to previous research, the risk of developing lung cancer decreases sharply and quickly after quitting smoking. According to a British study, the number of people who had lung cancer before the age of 75 fell from 16 percent to three percent among those who quit smoking before the age of 50.

The UmeÃ¥ researchers have compared the change in smoking habits in Sweden from the 1950s with the incidence of lung cancer between 1970 and 2021 in men and women aged 40–84 years. They studied how the risk varied among men and women in different age groups. Previous studies have shown that squamous cell cancer is the form of lung cancer that has the strongest association with smoking.

The results showed that the risk of being affected varied greatly depending on the type of lung cancer, age and gender. Based on previous studies, it would have been expected that the risk of cancer would have decreased among the elderly as well. However, lung cancer was as common in 1970 as in 2021 among men aged 75–79 years. The number of squamous cell cancer had fallen sharply, while in 2021 it had instead increased six-fold for the other common form of cancer, adenocarcinoma. The risk of squamous cell cancer had increased among women in the age group 75-79 years to the same level as among men. For adenocarcinoma, the risk was similar for women and men, despite the fact that there were large differences in smoking habits among women and men in the 1970s.

The study does not provide an answer as to why the development of lung cancer does not correspond well with expectations. For that, other types of studies are required. However, there are several possible explanations. One explanation may be that people may underreport their smoking, i.e. that the reduction in smoking may be smaller in reality. Another possible explanation may be that previous assumptions have been exaggerated about how quickly the risk of being affected decreases when you quit smoking. Nor can it be ruled out that other environmental or lifestyle factors may play a role; Even those who have never smoked can get lung cancer, although it is less common. The fact that the trend is so much worse for women than for men is due to the fact that Swedish women generally started smoking later in history than men.

“The results should certainly not be interpreted as it is useless to quit smoking. On the contrary, the study emphasizes the importance of quitting early, preferably never starting, as it may be the case that the risk of lung cancer is elevated for longer than we previously thought,” says Bengt Järvholm.

The study shows that if the risk of developing lung cancer in 2021 was as high as the risk in 1970 in men and women aged 40–84, approximately 2,250 men would have suffered from lung cancer in 2021 instead of 1695 cases, i.e. a decrease of 555 cases. Among women, there would have been 544 cases instead of the current 2,181 cases, i.e. there has been an increase of 1,637 cases of lung cancer.

The study is based on data from the National Board of Health and Welfare's cancer registry, which was compared with statistics on tobacco smoking from surveys and from the sale of cigarettes.

 

Why don't we stick to home physiotherapy exercises?



BEN-GURION UNIVERSITY OF THE NEGEV





BEER-SHEVA, Israel, April 2, 2024 – The lack of persistence in home physiotherapy exercises is a well-known problem hindering the effectiveness of treatment. It is especially evident in vestibular rehabilitation (exercises to treat dizziness and balance problems). Researchers from Ben-Gurion University of the Negev analyzed the barriers to conducting consistent home exercises and have published recommendations to overcome them in the leading physical therapy journal, The Journal of Neurologic Physical Therapy (JNPT).

Vestibular rehabilitation addresses abnormalities in the vestibular system, such as dizziness, gait instability, sensitivity to movement and blurred vision. Treatment is especially effective when consistently practiced at home.

To find a solution to the lack of consistent practice at home, a research group from the Department of Physiotherapy at Ben-Gurion University approached 39 patients doing vestibular rehabilitation and experienced physiotherapists to identify barriers.

 They found six barriers: motivation (lack of confidence in the effectiveness of the practice, boredom and lack of internal drive); increased symptoms during the practice (temporary worsening of dizziness, during or after the exercises); difficulties in time management (difficulty integrating practice into daily routine); lack of feedback and guidance (patients' limited understanding of how exercises should be done and their effect); psychosocial factors (what will the environment think?); and related medical deficiencies (such as neck pain and migraines).

The research team formulated recommendations for clinicians, which can significantly improve treatment outcomes and patients' quality of life. Thus, for example, to increase motivation – personal interaction and follow-up by a clinician would allow for greater attention to the exercises, availability and feedback conversations on the performance of the exercises – including initiated phone calls, text messages to patients in between visits to the clinic, would nurture motivation for the practice. Investing time and money should also increase motivation. In terms of time management – personalizing the exercises to fit into the patient's daily routine. For example, to practice a little bit at a time throughout the day and/or write in a daily diary. Patient guidance – the exercise instructions should include an explanation of the importance of the exercises, the expected symptoms, and the expected recovery time. Documenting improvement by providing quantitative and visual feedback, such as charts and graphs, should encourage continued practice.

"Our study provided a broad perspective for data analysis by both patients and treating physicians," explained Prof. Shelly Levy-Tzedek who led the research. "Identifying the common barriers to practice allowed us to build strategies that could improve adherence to home practices and, as a result, the effectiveness of treatment. This is a study that can be applied in any clinic and to any patient, and therefore an important guide for therapists."

This research was carried out as part of Liran Kalderon's doctoral dissertation in the Department of Physiotherapy at Ben-Gurion University of the Negev, under the joint supervision of Prof. Shelly Levy-Tzedek and Dr. Yoav Gimmon, and together with Azriel Kaplan and Dr. Amit Wolfovitz.

Photo Caption: Prof. Shelly Levy-Tzedek. Credit: Dani Machlis, Ben-Gurion University of the Negev: https://bgu.chorus.thirdlight.com/link/lvbxvpkl98qm-9xn58o/@/preview/1?o

 

Precise localization of miniature robots and surgical instruments inside the body



GERMAN CANCER RESEARCH CENTER (DEUTSCHES KREBSFORSCHUNGSZENTRUM, DKFZ)





In the medicine of the future, tiny robots will navigate independently through tissue and medical instruments will indicate their position inside the body during surgery. Both require doctors to be able to localize and control the devices precisely and in real time. Until now, there has been no suitable method for this. Scientists from the German Cancer Research Center (DKFZ) have now described a signaling method based on an oscillating magnet that can significantly improve such medical applications.

What until recently sounded like science fiction is now well advanced in development: Nanorobots that move independently through the body are expected to transport drugs, take measurements in tissue or perform surgical procedures. Magnetically driven nanorobots that navigate through the muscle, through the vitreous body of the eye or through the blood vessel system have already been developed.

However, there is a lack of sophisticated systems to track and control the activities of the robots deep inside the body in real time. Traditional imaging techniques are only suitable to a limited extent. Magnetic resonance imaging (MRI) is limited in temporal resolution, computer tomography (CT) is associated with radiation exposure and the strong scattering of sound waves limits the local resolution of ultrasound.

A team led by Tian Qiu from the DKFZ, Dresden site, has now invented a new method to solve this problem. The tiny device they have developed is based on a magnetic oscillator, i.e. a mechanically oscillating magnet located in a millimeter-sized housing. An external magnetic field can excite the magnet to vibrate mechanically. When the oscillation subsides again, this signal can be recorded with magnetic sensors. The basic principle is comparable to nuclear magnetic resonance in MRI. The researchers refer to the method as "Small-Scale Magneto-Oscillatory Localization" (SMOL). 

SMOL allows the position and orientation of the small device to be determined at a great distance (over 10 cm), very precisely (less than 1 mm) and in real time. In contrast to tracking methods based on static magnets, SMOL can detect movements in all six degrees of freedom and with significantly higher signal quality. As the device is based on weak magnetic fields, it is harmless to the body, wireless and compatible with many conventional devices and imaging techniques.

"There are many possible applications for the SMOL method," says Felix Fischer, first author of the current publication. "We have already integrated the system into miniature robots and instruments for minimally invasive surgery. A combination with capsule endoscopes or the marking of tumor tissue for very precise radiotherapy would be conceivable. Our method could also provide a decisive advantage for fully automated surgical robotics or augmented reality applications."

"SMOL only requires comparatively simple technical equipment. Due to its dimensions in the millimetre range, the oscillator can be integrated into many existing instruments, and there is still potential for further miniaturization. Thanks to its precise spatial and temporal resolution, our technique has the potential to significantly advance many medical procedures of the future," comments Tian Qiu, senior author of the current publication.

F. Fischer, C. Gletter, M. Jeong, T. Qiu: Magneto-oscillatory localization for small-scale robots.

npj Robotics 2024, DOI: https://doi.org/10.1038/s44182-024-00008-x

 

With more than 3,000 employees, the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) is Germany’s largest biomedical research institute. DKFZ scientists identify cancer risk factors, investigate how cancer progresses and develop new cancer prevention strategies. They are also developing new methods to diagnose tumors more precisely and treat cancer patients more successfully. The DKFZ's Cancer Information Service (KID) provides patients, interested citizens and experts with individual answers to questions relating to cancer.
To transfer promising approaches from cancer research to the clinic and thus improve the prognosis of cancer patients, the DKFZ cooperates with excellent research institutions and university hospitals throughout Germany:

National Center for Tumor Diseases (NCT, 6 sites)

German Cancer Consortium (DKTK, 8 sites)

Hopp Children's Cancer Center (KiTZ) Heidelberg

Helmholtz Institute for Translational Oncology (HI-TRON Mainz) - A Helmholtz Institute of the DKFZ

DKFZ-Hector Cancer Institute at the University Medical Center Mannheim

National Cancer Prevention Center (jointly with German Cancer Aid)

The DKFZ is 90 percent financed by the Federal Ministry of Education and Research and 10 percent by the state of Baden-Württemberg. The DKFZ is a member of the Helmholtz Association of German Research Centers.

Tuesday, April 02, 2024

 

Is it the school, or the students?


Study shows perceptions of “good” schools are heavily dependent on the preparation of the students entering them



MASSACHUSETTS INSTITUTE OF TECHNOLOGY





Are schools that feature strong test scores highly effective, or do they mostly enroll students who are already well-prepared for success? A study co-authored by MIT scholars concludes that widely disseminated school quality ratings reflect the preparation and family background of their students as much or more than a school’s contribution to learning gains. 

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. 

###

Written by Peter Dizikes, MIT News

Paper: “Race and the mismeasure of school quality”

https://www.aeaweb.org/articles?id=10.1257/aeri.20220292