Many people will be aware of the concept of publication bias. At its most basic level, this is where results are published if they suit the authors and/or funders and not published if they do not [suit the authors/funders]. However there are in fact lots of variations on this theme, and in the methods that could lead to people not coming to the right conclusion because of the way the data was presented (or not presented as the case might be). I happened to come across of the following paper which looks at this issue in depth. Fortunately one does not need to read a lot of the paper to read the bit I'm highlighting. http://bit.ly/eigZRY i.e. http://onlinelibrary.wiley.com/o/cochrane/clsysrev/articles/CD008965/pdf_fs.html The basic premise for this review is that the authors have become aware that not all the data has been published and they are investigating the issue through various means, checking for different types of bias. In tables 1 and 2, it tries to explain the different types of bias that the authors are checking for. There are 27 types in total. They are explained in fairly basic English I think in the sense that one does not need to know biology to understand the issues being raised. Unfortunately I think they could probably have given slightly more detailed descriptions/explanations in some cases. However there are papers they link to which give more detail for anyone interested. Generally, publication bias is associated with pharmaceutical companies. However is no reason why there may not be other types of bias. I think it would be interesting to look at the issue in relation to some nonpharmacological interventions for ME/CFS.