A new data visualisation showing the results of 106 clinical trials in multiple sclerosis over the past 30 years reveals possible publication bias. The tool was developed by the Multiple Sclerosis Discovery Forum (MSDF) and is the first in a series of visualisations they are creating in the hope that people will discover unexpected connections by examining data in different ways.
Their interactive bubble chart presents the key features of 106 clinical trials in MS involving over 44,000 patients. Trials included in the data set had to be published between 1985 and April 2014. The size of each bubble corresponds to the number of people enrolled in that trial, and different colours indicate trials with positive, negative, and neutral outcomes. Trials can be sorted in various ways, including by trial phase, by year, and by funding source.
Robert Finn, Executive Editor of MSDF:
I was demonstrating this visualization to one scientist, and he noticed something odd when he sorted the trials by phase. Of the approximately 60 phase 2 trials, only 10 had negative outcomes. It seemed to him that there ought to have been a far higher proportion of failed phase 2 trials. The hypothesis that seems most reasonable is that phase 2 trials with negative outcomes are less likely to be published than those with positive outcomes.
This is a shame: to avoid expensive and futile duplication it’s crucial that every negative trial sees the light of day. Failing to publish those studies also dishonours the patients who volunteered to put their bodies on the line for what they thought was a chance to advance scientific progress. Studies that aren’t published actually impede scientific progress.