The Placebo Effect

[psionl0]

You mean the one I posted in the OP?

"Adam ruins everything" is not a scientific study.

Discrediting an interview when the interviewee is not present is easy.

 

[arthwollipot]

"Adam ruins everything" is not a scientific study.

Discrediting an interview when the interviewee is not present is easy.

The link to The Lancet is a little bit further down. You have to read more than the first couple of paragraphs.

 

[psionl0]

The link to The Lancet is a little bit further down. You have to read more than the first couple of paragraphs.

All I saw was a link to a podcast of the interview,

 

[arthwollipot]

All I saw was a link to a podcast of the interview,

Yes, that's clear. You need to keep reading.

 

[Ziggurat]

The link to The Lancet is a little bit further down. You have to read more than the first couple of paragraphs.

I read through your link, although not the Lancet paper itself. But the quoted bit about both the real surgery and the "placebo" group both receiving physiotherapy seems pretty damning from an experimental design viewpoint. If the "placebo" group actually had an intervention (and physiotherapy is an intervention) that your control group did not, then it's not testing the placebo effect.

 

[arthwollipot]

I read through your link, although not the Lancet paper itself. But the quoted bit about both the real surgery and the "placebo" group both receiving physiotherapy seems pretty damning from an experimental design viewpoint. If the "placebo" group actually had an intervention (and physiotherapy is an intervention) that your control group did not, then it's not testing the placebo effect.

If both groups get the same intervention, then yes it's testing the placebo effect, since that's the only thing that was different between the two groups.

 

[Ziggurat]

If both groups get the same intervention, then yes it's testing the placebo effect, since that's the only thing that was different between the two groups.

There are actually three groups here: "real" surgery + physiotherapy, "placebo" surgery + physiotherapy, and no treatment. The first two groups had better outcome than the last group, and about the same as each other. There isn't one thing that's different between the placebo group and the control group, there are two things that are different.

One interpretation is that placebo surgery provides a benefit in this case, comparable to the benefits of real surgery, and both of which are better than no surgery. Another interpretation is that neither placebo surgery nor real surgery provide any benefit, and the benefit the first two groups show is due to the physiotherapy. As the authors admit in a quote from your link, they cannot distinguish between these two possibilities based on their data. In order to test the placebo effect here, we need to be able to eliminate the effects of physiotherapy. But we can't do that, because the study was poorly designed.

 

[psionl0]

If both groups get the same intervention, then yes it's testing the placebo effect, since that's the only thing that was different between the two groups.

I finally found the actual study and read the discussion. It is not testing the placebo effect but whether surgery was better than the placebo effect.

The fact the both groups received post operative care that the third group didn't doesn't prove that the placebo effect is not real. That wasn't specifically what was tested so to draw the conclusion that the placebo effect is imaginary is a non-sequitur.

 

[arthwollipot]

There are actually three groups here: "real" surgery + physiotherapy, "placebo" surgery + physiotherapy, and no treatment. The first two groups had better outcome than the last group, and about the same as each other. There isn't one thing that's different between the placebo group and the control group, there are two things that are different.

One interpretation is that placebo surgery provides a benefit in this case, comparable to the benefits of real surgery, and both of which are better than no surgery. Another interpretation is that neither placebo surgery nor real surgery provide any benefit, and the benefit the first two groups show is due to the physiotherapy. As the authors admit in a quote from your link, they cannot distinguish between these two possibilities based on their data. In order to test the placebo effect here, we need to be able to eliminate the effects of physiotherapy. But we can't do that, because the study was poorly designed.

I finally found the actual study and read the discussion. It is not testing the placebo effect but whether surgery was better than the placebo effect.

The fact the both groups received post operative care that the third group didn't doesn't prove that the placebo effect is not real. That wasn't specifically what was tested so to draw the conclusion that the placebo effect is imaginary is a non-sequitur.

You are both correct. However, this study was widely reported (including by Adam Ruinseverything) as saying that the placebo effect was just as good as the surgery, whereas what it actually said was that the surgery was no better than placebo. Which was the whole point of this discussion from the beginning.

 

[psionl0]

You are both correct. However, this study was widely reported (including by Adam Ruinseverything) as saying that the placebo effect was just as good as the surgery, whereas what it actually said was that the surgery was no better than placebo. Which was the whole point of this discussion from the beginning.

No, the whole point of this discussion was that "the placebo effect is largely a sham". This study didn't demonstrate that.

 

[arthwollipot]

No, the whole point of this discussion was that "the placebo effect is largely a sham". This study didn't demonstrate that.

Not on its own. But it was the point of this article by Mike Hall, which itself forms a part of the body of evidence that shows that the placebo effect is largely a sham. This particular part of the body of evidence shows that studies that say that a treatment is no better than a placebo are routinely misreported as saying that a placebo is as good as a treatment.

This is the other part that I'm trying to get you to understand: This one article is not the entire argument. Mike has promised to put more of the evidence he has collected - which up until now has only been in the form of unindexed podcast episodes - into the form of written articles in the future. I will report them here when they appear. Be patient.

 

[psionl0]

This particular part of the body of evidence shows that studies that say that a treatment is no better than a placebo are routinely misreported as saying that a placebo is as good as a treatment.

Those two statements are logically equivalent and I don't think that either form is misleading (and it only relates to one type of surgical procedure).

As far as demonstrating that the placebo effect is a sham is concerned, this study doesn't form part of a "body of evidence" that demonstrates anything of the sort.

 

[arthwollipot]

Those two statements are logically equivalent and I don't think that either form is misleading (and it only relates to one type of surgical procedure).

Yes, this is part of the problem. Because you see the two statements as logically equivalent, you are led to the belief that taking a placebo has real physiological effects that aren't otherwise explained by any of the many different variables.

As far as demonstrating that the placebo effect is a sham is concerned, this study doesn't form part of a "body of evidence" that demonstrates anything of the sort.

Now you're just looking for reasons to be contrary.

You haven't seen the rest of it yet! You're reading A Long-Expected Party and saying "This doesn't say anything about orcs or kings! How can it be a story about travelling to distant lands, great wars, and destroying evil? It's just a party!"

This particular part of the body of evidence demonstrates how evidence is misreported and misinterpreted, which leads to unjustified belief in the powerful placebo effect. Future parts will build on that.

 

[psionl0]

Yes, this is part of the problem. Because you see the two statements as logically equivalent, you are led to the belief that taking a placebo has real physiological effects that aren't otherwise explained by any of the many different variables.

No matter how hard you try, you won't fit that square peg in this round hole.

The only thing that this study showed was that in this case, there was no significant difference in the results of a real surgery and the sham surgery. Whether this was due primarily to a placebo effect or whether the postoperative physiotherapy made a difference (and whether this postoperative physiotherapy was also a placebo effect) was not really tested in the study.

It might be stretching it to conclude that the placebo effect is as "powerful" as surgery in general but it is stretching it further to suggest that this supports the notion that the placebo effect is a "sham".

The conclusion by the study that some surgeries are no better than a placebo is absolutely valid.

You haven't seen the rest of it yet! You're reading A Long-Expected Party and saying "This doesn't say anything about orcs or kings! How can it be a story about travelling to distant lands, great wars, and destroying evil? It's just a party!"

I'm sure that your blogger opened with the best example to support his belief that he could find. I doubt that future examples will be as "convincing".

 

[arthwollipot]

No matter how hard you try, you won't fit that square peg in this round hole.

The only thing that this study showed was that in this case, there was no significant difference in the results of a real surgery and the sham surgery. Whether this was due primarily to a placebo effect or whether the postoperative physiotherapy made a difference (and whether this postoperative physiotherapy was also a placebo effect) was not really tested in the study.

It might be stretching it to conclude that the placebo effect is as "powerful" as surgery in general but it is stretching it further to suggest that this supports the notion that the placebo effect is a "sham".

The conclusion by the study that some surgeries are no better than a placebo is absolutely valid.

*pinches bridge of nose real hard*

You're missing the point. Missing by a country mile.

We agree on what the study says. We agree on that. Now, would you like to take a look at what the article says? You know, the article by Mike Hall, published on the website of the UK Skeptic Magazine?

In case you missed it (you definitely missed it), the article uses the study, and an episode of Adam Ruins Everything, to illustrate how easy it is to misrepresent and misreport what a study says. The study says that the surgery is no better than placebo. Adam Ruinseverything says "Wow, this study shows that the placebo effect is really powerful!"

That's the point of the article. It establishes how the myth of the "powerful placebo" takes hold in the public consciousness. As, apparently, it has taken hold in yours. That's part of why Mike did all that work in the first place - because people who are otherwise smart and skeptical like Ben Goldacre (and, apparently, you) have completely swallowed the "powerful placebo" idea.

I'm sure that your blogger opened with the best example to support his belief that he could find. I doubt that future examples will be as "convincing".

Now you're reading "A Long-Expected Party" and saying "Because this doesn't say anything about orcs and kings, I doubt that the rest of the book is any good."

 

[Ziggurat]

You are both correct. However, this study was widely reported (including by Adam Ruinseverything) as saying that the placebo effect was just as good as the surgery, whereas what it actually said was that the surgery was no better than placebo. Which was the whole point of this discussion from the beginning.

Ok.

But in case it wasn’t clear from my earlier exchange with Hans, I’ve only ever defended what one might term “weak” placebo, not what’s sometimes being called strong placebo. The OP seems to claim all forms of placebo effectiveness are false.

 

[arthwollipot]

Ok.

But in case it wasn’t clear from my earlier exchange with Hans, I’ve only ever defended what one might term “weak” placebo, not what’s sometimes being called strong placebo. The OP seems to claim all forms of placebo effectiveness are false.

"Weak" placebo is largely explained by uncontrolled variables. The argument is, and always has been, about "strong" placebo - the claim that (for example) even if homeopathy is a placebo, it still works and it's therefore okay to take and for doctors to prescribe.

We as skeptics largely don't believe that (though I have seen it argued on this forum), but a lot of people do. Including, apparently, Adam Ruinseverything.

 

[Ziggurat]

"Weak" placebo is largely explained by uncontrolled variables.

I don't think that's true.

 

[psionl0]

In case you missed it (you definitely missed it), the article uses the study, and an episode of Adam Ruins Everything, to illustrate how easy it is to misrepresent and misreport what a study says. The study says that the surgery is no better than placebo. Adam Ruinseverything says "Wow, this study shows that the placebo effect is really powerful!"

Sure, as I have stated previously, we have a case where ONE person misrepresented the results of ONE study involving the placebo effect.

What I take exception to is the implication that this means that ALL people misrepresent the results of ALL studies involving the placebo effect or that this proves that the placebo effect is a "sham".

 

[arthwollipot]

Next article is up:

The idea that four placebo pills are more powerful than two sounds magical – because it isn’t true

In 2001, the New England Journal of Medicine published a study titled Is The Placebo Powerless? An Analysis of Clinical Trials Comparing Placebo with No Treatment.

This was an influential review, prompting follow-ups in 2004 and 2010, the latter of these being for the Cochrane Collaboration. Each of these papers draws comparable conclusions: there is little evidence placebos have powerful clinical effects, and such effects which are measured are difficult to distinguish from bias. Despite this, the narrative of the ‘powerful placebo effect’ persists.

One of the more common claims made for the strange and magical power of the placebo is that peptic ulcers heal faster when you take four placebo pills, rather than two. This is clearly an extraordinary claim. Four inert pills clear ulcers faster than two inert pills? Four times zero is greater than two times zero? Could this really be true?

Make sure you go to the article, because there are links.