I woke up this morning to two very different bits of news that really put the world in perspective. First, a friend of mine delivered a talk on how research studies are carried out and how people in the field of mental health should “analyze” them, no pun intended. It was a good talk, and I could tell that it was difficult for him to explain to his audience the difficult concepts of biostatistics and research studies. These are difficult concepts, as my friend put it.
See, there is a hierarchy to research studies. Graphically, that hierarchy looks like this:
It’s in the shape of a pyramid to distinguish the amount of these types of studies out there. There are a ton of editorials and way fewer systematic reviews. However, systematic reviews are better than all other studies (from an evidence point of view) because they’ve adjusted for biases and other internal and external threats to validity. Epidemiological studies (Case-Control, Cohort, and Randomized Controlled Trials), are in the middle of the pyramid, and they’re how we go from case series to systematic reviews. Epidemiology, as you can see, is what holds the whole goddamn thing up.
This is how reasonable, science-oriented people see evidence. We trust editorials and case series, but we need that science to make sure that what we’re seeing is not based on our own biases and is not the result of chance. Just ask Wakefield how it went when he went backwards and issued his “expert opinion” that the MMR caused autism when his case series paper showed no association between the two things. Even people who are not scientists want to make sure that policy is driven by evidence. Otherwise, you’re just doing things because they feel good, and the chances of failure are multiplied endlessly when you do that.
(CONTENT IN THIS SECTION DELETED AT THE REQUEST OF KAREN ERNST)
Copyright infringements aside, the intent of this woman,
as you can see, is to (once again) collect anecdotes from people who are convinced that vaccines “stole” their children. So I went on Facebook and asked a pertinent set of questions, as you can see:
“I know that some pro-vax “sciency” people are probably going to give you a hart time for this, but, personally, I’m looking forward to [how] you collect the data, analyze it, and present it to us. Quick question: Where will you draw the control group from? People who have not been harmed by vaccines? [An anathema to antivaxxers.] And how will you collect THAT data? Or are you going the case series route? ‘Cos case series don’t really rank well in the hierarchy of evidence.”
Now, I’m only making an assumption here, but I bet you dollars to doughnuts that “DK,” who commented after me, went to look at what “hierarchy of evidence” meant, and made what is perhaps the most idiotic statement from an anti-vaccine activist I’ve read this week (besides the ramblings of some petulant kid). As you can see above, she wrote:
“Individual cases and even (horrors) stories are part of the pyramid of evidence based medicine. Epidemiological studies are not. True, individual case histories are at the bottom of the pyramid, but there they are.”
Read it again: “Epidemiological studies are not.”
I must be seeing things. Because I see “case control,” “cohort,” and “randomized clinical trials” right there. Am I crazy?
Of course I’m not. Ren saw the same thing in his presentation yesterday. The people who attended saw the same thing. When I studied for my MPH, my professors and my colleagues saw it.
We all [expletive] saw it!!!
Except for the people who have eyes and won’t see.