Randomized controlled trials require hard work and financial commitment, whereas meta-analyses and systematic reviews can be relatively easy to perform and often get published in high impact journals. Many researchers might decide to devote themselves to the latter approach, resulting in a negative impact on clinical research. We have reviewed the number of indexed meta-analyses and systematic reviews on PubMed and compared it with the number of randomized controlled trials over the same period. Statistical analysis showed an exponential increase of synthetic studies with respect to randomized trials. The ratio between RCTs and synthetic studies is quickly decreasing. These results suggest that a growing number of researchers might prefer to commit themselves to synthetic studies more than be involved in more time consuming and funds demanding observational trials. If we are unable to invert this trend, in the future we will have a growing number of synthetic studies utilizing someone else's original data and fewer raw data to base our knowledge upon.
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