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  • One simple vitamin can reduce your risk of heart disease.

  • Eating chocolate reduces stress in students.

  • New drug prolongs lives of patients with rare disease.

  • Health headlines like these are published every day,

  • sometimes making opposite claims from each other.

  • There can be a disconnect between broad,

  • attention-grabbing headlines and the often specific,

  • incremental results of the medical research they cover.

  • So how can you avoid being misled by grabby headlines?

  • The best way to assess a headline's credibility

  • is to look at the original research it reports on.

  • We've come up with a hypothetical research scenario

  • for each of these three headlines.

  • Keep watching for the explanation of the first example;

  • then pause at the headline to answer the question.

  • These are simplified scenarios.

  • A real study would detail many more factors and how it accounted for them,

  • but for the purposes of this exercise,

  • assume all the information you need is included.

  • Let's start by considering the cardiovascular effects

  • of a certain vitamin, Healthium.

  • The study finds that participants taking Healthium

  • had a higher level of healthy cholesterol than those taking a placebo.

  • Their levels became similar to those of people with naturally high levels

  • of this kind of cholesterol.

  • Previous research has shown that people with naturally high levels

  • of healthy cholesterol have lower rates of heart disease.

  • So what makes this headline misleading:

  • "Healthium reduces risk of heart disease."

  • The problem with this headline is that the research didn't actually investigate

  • whether Healthium reduces heart disease.

  • It only measured Healthium's impact

  • on levels of a particular kind of cholesterol.

  • The fact that people with naturally high levels of that cholesterol

  • have lower risk of heart attacks

  • doesn't mean that the same will be true of people

  • who elevate their cholesterol levels using Healthium.

  • Now that you've cracked the case of Healthium,

  • try your hand at a particularly alluring mystery:

  • the relationship between eating chocolate and stress.

  • This hypothetical study recruits ten students.

  • Half begin consuming a daily dose of chocolate,

  • while half abstain.

  • As classmates, they all follow the same schedule.

  • By the end of the study, the chocolate eaters are less stressed

  • than their chocolate-free counterparts.

  • What's wrong with this headline:

  • "Eating chocolate reduces stress in students"

  • It's a stretch to draw a conclusion about students in general from a sample of ten.

  • That's because the fewer participants are in a random sample,

  • the less likely it is that the sample will closely represent

  • the target population as a whole.

  • For example, if the broader population of students is half male and half female,

  • the chance of drawing a sample of 10

  • that's skewed 70% male and 30% is about 12%.

  • In a sample of 100 that would be less than a .0025% chance,

  • and for a sample of 1000,

  • the odds are less than 6 x 10^-36.

  • Similarly, with fewer participants,

  • each individual's outcome has a larger impact on the overall results

  • and can therefore skew big-picture trends.

  • Still, there are a lot of good reasons for scientists to run small studies.

  • By starting with a small sample,

  • they can evaluate whether the results are promising enough

  • to run a more comprehensive, expensive study.

  • And some research requires very specific participants

  • that may be impossible to recruit in large numbers.

  • The key is reproducibility

  • if an article draws a conclusion from one small study,

  • that conclusion may be suspect

  • but if it's based on many studies that have found similar results,

  • it's more credible.

  • We've still got one more puzzle.

  • In this scenario, a study tests a new drug for a rare, fatal disease.

  • In a sample of 2,000 patients,

  • the ones who start taking the drug upon diagnosis

  • live longer than those who take the placebo.

  • This time, the question is slightly different.

  • What's one more thing you'd like to know before deciding if the headline,

  • "New drug prolongs lives of patients with rare disease", is justified?

  • Before making this call,

  • you'd want to know how much the drug prolonged the patients' lives.

  • Sometimes, a study can have results that,

  • while scientifically valid, don't have much bearing on real world outcomes.

  • For example, one real-life clinical trial of a pancreatic cancer drug

  • found an increase in life expectancyof ten days.

  • The next time you see a surprising medical headline,

  • take a look at the science it's reporting on.

  • Even when full papers aren't available without a fee,

  • you can often find summaries of experimental design

  • and results in freely available abstracts,

  • or even within the text of a news article.

  • It's exciting to see scientific research covered in the news,

  • and important to understand the studies' findings.

One simple vitamin can reduce your risk of heart disease.

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この奇妙なトリックはクリックベイトを見抜くのに役立つ - Jeff Leek & Lucy McGowan (This one weird trick will help you spot clickbait - Jeff Leek & Lucy McGowan)

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    April Lu に公開 2021 年 01 月 14 日
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