‘Publication bias’ is a very interesting and very human phenomenon. For a number of reasons, positive trials are more likely to get published than negative ones. It’s easy enough to understand, if you put yourself in the shoes of the researcher. Firstly, when you get a negative result, it feels as if it’s all been a bit of a waste of time. It’s easy to convince yourself that you found nothing, when in fact you discovered a very useful piece of information: that the thing you were testing doesn’t work