The New York Times ran a guest essay Tuesday highlighting a COVID-19 study that broke one of the most basic rules of scientific research.
The essay was written by Dr. Kanecia Zimmearman and Dr. Danny Benjamin Jr., both of Duke University, and argued that universal masking in school leads to a major drop in COVID-19 transmission by the kids and adults within. There’s just one problem: The study had no control group.
The authors highlighted the ABC Science Collaborative, a project they set up with colleagues in North Carolina to collect data from more than 1 million students, faculty and staff in the state’s schools. The project found that between March and June 2021, more than 7,000 adults and kids attended school while infected with COVID-19, but only 363 additional children caught coronavirus in those communities. The authors argue this proves the effectiveness of universal masking in limiting community spread within education environments.
However, as pointed out on Twitter by author David Zweig, the study has no control group to compare to. Zimmerman and Benjamin Jr. cited an outbreak at a school in Israel without universal masking and social distancing in which 153 students and 25 staff members were infected, as well as outbreaks at summer camps in Texas, Illinois and Florida. (RELATED: ANALYSIS: Pfizer Is Lobbying The Government For Third Vaccine Doses, And It Could Make Them Billions)
Yet schools in Florida, and more so throughout many parts of Europe did not and do not have mask mandates for kids, with varying age cutoffs, and there is no correlated explosion of cases originated in those schools
— David Zweig (@davidzweig) August 10, 2021
The authors do the same thing in this Opinion piece, citing some districts that had mask mandates and low transmission as evidence of their effectiveness, and cherry picking some places that didn’t to suggest the opposite…
— David Zweig (@davidzweig) August 10, 2021
Zweig said he contacted the researchers to inquire about the omission of a control group. They allegedly cited the Israeli study. When Zweig pointed out the issues with the Israeli example, such as the fact that it was for grades 7-12, schools were exempt from masking due to a heatwave and all the windows in the schools were kept closed, he said the researchers stopped responding to his emails.
When I raised the points about the Israeli study the authors stopped responding to me
END
— David Zweig (@davidzweig) August 10, 2021
Typical circumstances dictate that one study cannot simply use another study to claim findings against, and a control group in which the intervention being studied isn’t deployed must be used. The Duke researchers only point to other outbreaks in mask-less settings and a lack of outbreaks in schools with mask mandates to back up their findings. There is no evidence, however, that the same North Carolina schools would have had larger outbreaks if all policies had been the same except for masking.