Coffee drinking linked to longer life

define link: A relationship between two things or situations, esp. where one thing affects the other

define correlation: A mutual relationship or connection between two or more things

The definitions are close enough that even amongst the math/science researchers I work with, the words are frequently used interchangeably.

Everything else in the article talks in terms of "maybe", "plausible", "associated" and so on. All words that don't imply causation, nor rule it out. Further, the article is careful to point out that:

The explanation for the study findings "might not specifically be the coffee," Fisher says. "It might be some characteristic of the coffee drinker."

I'n all, I found it to be pretty good "science for the layman" reporting - to the point where I was surprised at how good it was.

I'll use this post as an excuse to mention the Lothian Birth Cohort. A really cool dataset of IQ test results at age 11 for (almost) all Scottish kids born in 1921 and 1936. While IQ tests are flawed in many ways, these data offer some means of control for follow up studies on these individuals. Many apparent effects disappear after controlling for age 11 IQ, for example: drinking coffee on intelligence — http://www.ncbi.nlm.nih.gov/pubmed/19995882 — nicely demonstrating the confounding problems affecting most studies.

Edit in response to sibling comment: yes, studies do try to control for these things. But it's hard, and often not really possible. This particular study might be ok, but we're not going to tell from a CNN article. We're also used to enough contradictory and over-hyped results in the popular press to know not to trust journalists to be a good filter.

Of course. And that's why they are in the history books.

But now the most part of "scientific studies" have two objectives:

- Meet grant / tenure criteria of published papers

- Prove the new drug by "Big Pharma" is better than the old one whose patents are expiring. The fact that several are disproved afterwards is irrelevant.

At least we still have the LHC guys, the Hubble guys, MSL, AMS. But don't be surprised if those are accused of not being "real scientists" as well.

That said, I agree with the sentiment here (and of the siblings) that controlling this sort of study is rather difficult.

IMO 95% of the health studies that catch fire in the popular press are repeated rediscoveries of class (smoking, fast food and types of food, etc.), or the qualities of illness (people who sit more die earlier, people who are depressed die earlier, etc.)

They did mention controlling for smoking, though, because they found that it counted against them.