She’s right to be worried! There are so many possible cracks that bias can seep through, nudging clinical trial results off course. Some of the biggest come from people knowing which comparison group a participant will be, or has been, in. Allocation concealment and blinding are strategies to reduce this risk.
Blinding and randomisation are often held up as best practice for clinical trials, but the reality is a lot less certain than many people realise and the ethical challenges aren’t trivial. We’ve included links to a long list of items reflecting on the ethics of trials.
And we’re counting on a lot of people here, aren’t we? There are the ones who enter an individual into one of the comparison groups in the trial. There are those individual participants themselves, and the ones dealing with them during the trial – healthcare practitioners who treat them, for example. And then there are the people measuring outcomes – like looking at an x-ray and deciding if it’s showing improvement or not.