“Little work at home can lead to weight problems in women.” With this news, I’ve been opening a critical thinking course for eight years now. The study about the use of time at home was widely in the news at the time. Even Medscape, a trusted source of medical news and information for doctors, was titled “Historic decline in housework contributes to female obesity.”
The interest in this study was the reason for holding the course. I was stunned that so many leading news outlets wrote about the investigation without criticism. Their stories seem quite plausible: since 1965, the beginning of the study, women spend less time doing household chores, which contributed to the increase in obesity. Perhaps, but this conclusion did not follow from the investigation, and no journalist saw it.
It still amazes me how easy it is for people, including journalists, to assume that science will make sense. Why is it like that? Is it a dread of science? Is the science expected to be too complex for the average person to understand? There is a lot of complex science, but studies like home study is not one of them, it is better to understand it. This is what the course teaches.
Last week I gave the news to a new group of thirty undergraduate students with a question: What kind of study is behind the news? Students are first through fourth year students from various fields of study, from health sciences to Jewish studies and dance. Only two of the students completed a course in epidemiology.
At the beginning of the course, most students do not know what to do with this question. They have no idea how to conduct scientific research. That’s why I’m going to give you a cross-section of what you might be wondering. Who are the participants? How long does the investigation take? What data is collected? But also: How do researchers know that limiting household tasks is exactly what leads to obesity?
We define research on the basis of these questions. A long-term cohort study in which a group of women is asked every few years to track how they spend their time and weigh themselves for a week is consistent with the conclusion that less time in the family can lead to weight problems. With this data, you can check whether the change in time usage is related to the weight change. Whether you can conclude that less household chores can “lead” to obesity depends on whether you are able to rule out alternative explanations: those who spend less time in the kitchen may eat ready meals more often – what’s the culprit?
But the study was not a group study. The data came from a US diary study in which a new group of women kept diaries of their time every five years from 1965 to 2010. These diaries showed that over the 45-year period, women spent less and less time on housework and more and more time sitting in front of the TV or Computer. This was him. No measures were used in the entire study.
The relationship between housekeeping and obesity has not been studied. It was speculation, a suggestion. Because obesity has increased during the same period. The fact that women began working outside the home en masse during the same period and burned their energy elsewhere was not taken into account. The role of diet has also not been investigated. Nor does it from soft drinks. The research was funded by The Coca-Cola Company.
This example is an extreme, but not an exception. In the coming weeks we’ll be discussing the science behind the current news stories in the course, and I don’t expect a shortage of examples this time around either. why not? Because news reports often rely heavily on press releases from universities and research institutes, these reports primarily highlight what makes the study special and newsworthy. There is no place for critical comments.
Here’s where things go wrong. These caveats are essential. The conclusion stands or falls with how the research is prepared. I don’t find it surprising that vitamin D supplements do not help depression when I read that 90 percent of participants are not vitamin D deficient.
And this number push up I find it highly implausible that someone would do this in a row to predict cardiovascular risk when I read that the participants, who were fit firefighters, had to do push-ups at a rate of eighty times per minute and actually lost weight if they missed three pendulum strokes. . Such details put the conclusions in a different light.
My students will not be able to read a news article without asking questions at the end of the course. Then they know a lot of the news isn’t what it seems and they are able to figure out what’s behind it. I feel proud to be able to teach them that.
Cecil Janssens Professor of translational epidemiology at Emory University in Atlanta.
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