One simple vitamin can reduce your risk of heart disease.
一種簡單的維他命就可以 減少你得到心臟病的風險。
Eating chocolate reduces stress in students.
學生吃巧克力可以減少壓力。
New drug prolongs lives of patients with rare disease.
新藥品延長罕見疾病病人的壽命。
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?
每天都可以看到 像這類的健康標題被刊出, 有時,這些標題的主張還彼此相反。 這些廣泛、吸引注意力的標題 和它們所報導的那些通常很明確、 漸進式的醫療研究結果 之間會有斷層。 所以,我們要如何避免 被聳動的標題誤導?
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.
評估標題可信性的最佳辦法 就是去看它報導的原始研究。 我們針對前述這三則標題分別 提出了一個假設性的研究情境。
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.
繼續看第一個例子的說明; 接著在標題出現後 按暫停,回答問題。 這些都是簡化的情境。 真實的研究會詳細說明更多因子 以及它們與研究的關係, 但為了做這項練習, 就假設所需的資訊已全被納入。
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.
咱們先來思考一下 一種維他命 Healthium 對心血管的影響。 該研究發現吃 Healthium 的受試者的 高密度脂蛋白膽固醇(HDL 好膽固醇) 比吃安慰劑的要來的高。 前者的膽固醇值很接近那些 天生就具有高水平好膽固醇的人。 先前的研究顯示 天生就具有高水平好膽固醇的人 比較不會罹患心臟疾病。
So what makes this headline misleading: "Healthium reduces risk of heart disease."
那麼,這標題是怎麼誤導的: 「Healthium 降低心臟疾病的風險」?
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.
這個標題的問題是, 研究並沒有真正去調查 Healthium 是否會減少心臟疾病。 它只是測量了 Healthium 對於特定種類膽固醇水平的影響。 那種膽固醇天生就很高的人 比較少有心臟病, 這並不一定表示 用 Healthium 來提高 膽固醇水平的人亦會如此。
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.
現在,你破解了 Healthium 的案例, 試試看這個特別誘人的謎: 吃巧克力和壓力之間的關係。 這項假設性研究招募了十名學生。 其中一半學生開始 每天吃一定劑量的巧克力, 另一半則避吃巧克力。 他們都是同學,所以課表一樣。 在研究尾聲,吃巧克力的人 比不吃巧克力的人壓力小。
What’s wrong with this headline: "Eating chocolate reduces stress in students"
這個標題有什麼問題: 「吃巧克力會減少學生壓力」
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.
樣本只有十個人,卻把結果套用到 所有學生,這就是過度擴大。 原因是,在隨機樣本中的 受試者人數越少, 該樣本就越無法代表 整個目標整體。 比如,如果廣大的學生母體中 有一半是男性,一半是女性, 抽出十個人做為樣本, 此樣本有 12% 的可能性 會偏向七成男性、三成女性。 若是一百人的樣本, 此機率則不到 0.0025%, 若樣本中有一千人, 此機率不到 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.
同樣的,當受試的人數很少時, 個別受試者的結果 對整體結果的影響會比較大, 因此可以造成整體趨勢的偏差。 不過,科學家還是有很多 好理由去進行小型研究。 從小樣本開始, 他們可以評估結果是否夠理想, 再來進行更全面、廣泛的研究。 有些研究會需要非常特定的受試者, 可能無法讓很多人參與。 關鍵在於可重複性: 如果文章從一項小型研究得出結論, 那結論可能不可信; 但如果文章的根據是 很多項發現類似結果的研究, 就會比較可信。
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.
我們還有一個謎要解。 這個情境中的研究,是在測試 治療致命罕見疾病的新藥。 樣本是兩千名病人, 被診斷出此疾病後 就開始吃這種藥的人, 比吃安慰劑的人活得更久。
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?
這次,問題有點不同。 你還需要知道哪一項資訊, 才能判斷這個標題是否合理: 「新藥延長了罕見疾病患者的生命」?
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 expectancy— of ten days.
在做決定之前, 你需要先知道,這種藥 能延伸病人多長的壽命。 有時研究的結果可能在科學上有效, 但對現實世界的結果影響不大。 比如,胰藏癌藥物的實際臨床試驗 發現可以延長壽命「十天」。
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.
下次看到驚人的醫療相關標題時, 先看一下它所報導的科學。 即使需要付費才能 看到完整研究論文, 你通常仍然能在免費取得的摘要中 找到實驗設計的概要以及結果, 或甚至在新聞文章的內文中找到。 見到新聞報導科學研究讓人振奮, 而重要的是要了解研究的發現。