Helen MacDonald

I'll fill you in on those details, courtesy of the authors of the paper.

So you're on the right track.

There was a couple more things.

For example, if people start to believe that they're not getting the active treatment, that might bias the way that they report, particularly self-reported outcomes.

And that could work either way, I guess, whether they thought they were on the treatment or not.

The other thing is that increasingly patients are quite curious and empowered to try and work out which group they are in.

And in the kind of digital age that we're in, there are examples of patients coming together and kind of pooling their outcomes and sharing their results and effectively unblinding the study themselves.

Yes, well, it may do.

There was also some interesting information about the assessors as well, that assessors can become unblinded, particularly, for example, if there's a medical emergency, perhaps a serious potential adverse outcome, and you have to find out whether the patient was on the active treatment or the placebo.

And the fact that that experience and knowing what that adverse outcome was might influence the way that that assessor deals with other patients

people in the trial.

I think the other interesting thing was on this issue of the kind of intention sort of writing about your intention to do a blinded study versus actually being able to say that it was convincingly blinded and it felt like reading between the lines of the paper there are some methodological difficulties and trickiness around

assessing how successful blinding actually has been and the authors of this say that only about two percent of trials actually report on the success of blinding and in part that may be because consort which is the reporting statement for randomized control trials doesn't suggest that you need to do this but nonetheless I wonder if it is because it's quite a difficult issue.

What's the Zelen?

So we've put, I suppose, a lot of confusion in everyone's minds now, but this paper does go on to give us some potential solutions.

And I guess it gives you a reminder that on one hand, you want an unbiased study.

But on the other hand, you're also trying to get information that actually helps you make decisions in the real world for real patients.

And sort of describes that the treatment effect from blinded studies is

can be quite different to real world settings where things like the placebo effect in a way are relevant and perhaps useful and part of what you want to see so they suggest thinking of trials as a kind of continuum where perhaps the closer you get to big pragmatic trials perhaps the more acceptable unblinding is likely to be and talk about whether um

there should be a stronger emphasis on the assessors of the outcomes being blinded rather than sort of everybody being blinded.