The replication drive in psychology continues to inspire debate. Simone Schnall has recently published a set of views which I think has potential to helpfully advance a conversation about replication research. In her discussion, one analogy struck me as particularly interesting: that to clinical trials. Schnall suggests that crowdsourced replications of clinical trials would be absurd. Surely, we can’t have patients organizing themselves into trials spontaneously, buying over-the-counter drugs, and reporting their outcomes online?
Possibly not. But we can have patients and doctors working together to do it, and for a wide range of clinical questions. Ideally, if there is uncertainty about what treatment would be best for me, my physician should key in my information into a computer and receive an immediate offer to randomize me to either of several reasonable treatment options. My health outcomes would then be automatically transferred into a clinical outcomes registry. Once enough patients have been randomized and results are conclusive, we will know which treatment is best, and then we can move on to the next question and keep randomizing. What I have just described is a randomised registry clinical trial. These trials can and will be implemented step by step into health systems that are able to monitor outcomes well.
Randomized registry trials can be used not only to test new treatments. They can also replicate clinical trials cheaply and easily. And we sorely need it. Think about it: Randomized controlled trials, in spite of ever-present challenges and limitations, tend to provide reasonably good evidence for the effect of a drug among the patients in the trial. But are you like those patients? Maybe the trial was done 20 years ago. Maybe the trial included only men, and you are a woman. Maybe you have another disease besides the one for which you are taking this drug. To catch moderating factors like these we need another trial. There is no end. To keep improving, we must keep randomizing, keep replicating, and keep extending our clinical questions.
Thus, randomized registry trials can be thought of in a sense as crowdsourced replications. They can be used for direct replications to improve estimates of treatment effects when evidence is inconclusive. They can also be used to verify the external validity of concluded clinical trials, i.e. to test whether a treatment really works in other people, in other places, and in this day and age. Compared to regular clinical trials, they can be a cheap and effective way to improve the evidence base for shared decision making.
Schnall advances two main counterarguments. First, she worries that patients’ confidence in drugs may be undermined. In my opinion, that would be likely to happen mostly if confidence was too high in the first place. If we show that another treatment option has stronger benefits, we will have done the patients a great service. They can then discuss their treatment options with their physicians again, and benefit from a new incremental increase in survival, quality of life, and/or decrease in costs. Here is a direct analogy to basic research. If we can succeed in undermining confidence in results that are not true, then the scientific community and the general public will benefit.
Schnall also suggests that pharmaceutical companies will not like to have their results replicated, because it may harm their reputation if the replication fails. I hope it is true that pharmaceutical companies’ concern for their reputation is a factor that helps to keep them from making unsupported claims about their products. But if they did so anyway, patients and physicians have a right to know. It is well known that industry-sponsored clinical trials have considerable publication bias, leading to inflated effect estimates. Patients of flesh and blood are harmed every day as a result. Pharmaceutical companies can improve their reputation by publishing all their trial data. Again, the analogy to basic research holds. Publication bias and other questionable practices distort the literature to some extent in every field. We researchers can protect our reputations by practicing science openly.
Clinical trials are an interesting model for other kinds of research. The lesson is not to replicate less, nor to avoid crowdsourcing. On the contrary, the lesson is to always keep measuring effects and to continuously update cumulative meta-analytic estimates. These are a few thoughts, which I offer in the hope of contributing to a constructive conversation about replication research.
Gustav Nilsonne, MD, PhD is a researcher at Stockholm University and Karolinska Institutet. You can reach him at firstname.lastname@example.org