Cochrane review of intercessory prayer: a pillar of shame for Cochrane

One of the most absurd interventions in healthcare is distant healing, which includes prayer.  We have shown that a Cochrane review of intercessory prayer[1] goes beyond reason, is logically inconsistent, and uses an unsound mixture of theological and scientific arguments,[2] which led to utter nonsense.

The review included ten trials aimed at testing if praying to a god can help those being prayed for. This idea involves three assumptions that are all extremely unlikely to be true: The existence of a god; that prayer can somehow travel in space and reach this god or works through a mechanism unknown to science; and that this god is responsive to prayer and can influence what would otherwise have happened.

The Cochrane authors ignored that a suspicion of fraud had been raised against a large trial, and that the largest “trial” was meant to amuse. They said that “outcomes of trials of prayer cannot be interpreted as ‘proof/ disproof’ of God’s response to those praying,” and that they attempted to quantify an “effect of prayer not dependent on divine intervention.”

This is nonsense. Why would people pray to a god if an effect of prayer is not caused by divine intervention, and what would then be the causal mechanism? The authors provide no explanation, and it is hard to imagine how prayer for ill people located at the other side of the globe (as in one of the trials), and who were unaware that someone prayed for them, could have an effect without assuming divine intervention.

It is also hard to accept that a god would help Brian in bed A, because someone, after randomisation, was asked to pray for him, but not the less fortunate Paul in bed B. The authors contradict themselves when they say that their review focuses on people, “setting time aside to communicate with God,” as the review is not about divine intervention.

They are also inconsistent when they note that, “If understanding of God is as limited as the Holy Literature suggests (1 Corinthians 13:12), the consequences of divine intervention may be considerably more subtle than could be measured in the crude results of a trial.” If that was a real concern, the authors should not have undertaken the review, because their reservation means that people doing trials of prayer cannot rely on what they observe.

Arguments like these are often used by practitioners of alternative medicine. They say that the research setup makes it impossible to study the real effect of their treatments. For example, they say that their treatments cannot be studied in randomised trials because the experimental setup destroys the effect. This falsehood is a perfect example of immunisation of the null hypothesis, which is that the treatment doesn’t work. The null hypothesis cannot be rejected. They also confuse randomisation with blinding when they say their treatments cannot be studied in randomised trials because they cannot be blinded. There are numerous trials of interventions that cannot be blinded, e.g. of psychotherapy and surgery, and we have learned a lot from these trials.

Regardless of the experimental results obtained, believers will be unaffected and will continue claiming with equal conviction that their treatments are effective.

Another statement also belongs to the realm of mysticism. The authors write that, “An omnipotent God would make concealment of allocation (of the participants to prayer or no prayer) impossible and may be noncompliant with the limitations of a randomized trial (Psalm 106:14,15, Job 42:2).”

Since a god could interfere with the experimental setup, it is difficult to understand why the authors excluded trials in which the treatment allocation was not concealed, and why they bothered to discuss the level of concealment in the trials they included.

The largest trial was published in BMJ’s Christmas issue and was meant to amuse, as the trial evaluated the effect of prayer 4-10 years after the patients had either left the hospital alive or had died from their bloodstream infection. Thus, the trial evaluated the effect of retroactive intercessory prayer using historical data and its author argued that we cannot assume “that God is limited by a linear time.” The Cochrane authors did not mention that the patients were randomised many years after their outcomes had occurred and did not discuss the likelihood that time can go backwards, or that prayer can wake the dead.

The retroactive prayer study reported a nonsignificant reduction in death for those prayed for but since it carried 75% of the weight in the meta-analysis in the Cochrane review, it led to a statistically significant effect of prayer.

Two years later, also in the Christmas issue, advocates for alternative medicine, prayer and healing tried to explain why the results of the retroactive study could be true using arguments from quantum theory.[3] They took their arguments seriously, even though they were nonsense, which a physicist demonstrated a year later – also in the Christmas issue.[4]

The Cochrane authors published this tautology: “A caring God may not wish to prolong suffering, so death therefore might be a positive outcome of prayer.” This is a perfect immunisation of the null hypothesis that makes trials of prayer meaningless. If people survive, it is good for them, and if they die, it is also good for them.

Amusingly, as the review is characterised by delusional thinking, it was published in the Cochrane Schizophrenia Group. We informed the editor, psychiatrist Clive Adams, about the major problems, and he suggested we published a comment alongside the review, which we did. He assured us the review wasn’t a joke, which only increased our amusement.

The review was updated in 2009 after we had criticised it, but the authors still included the study of retroactive prayer, justifying it with mysterious arguments. They called it a “relevant study,” “not in jest,” but “a rather serious paper.” They also said that “retrospective prayer is practised by some people,” and that the study was double blind since those praying did not know the outcome for any of the patients.

Perhaps they didn’t, but as the outcome was already known for all patients, it is wrong to give a fake study bonus points for being “double blind.” The Cochrane authors perverted the methodological principles without being aware they made themselves laughable.

On the possibility of waking the dead through prayer, they said: “Retrospective prayer may be considered theologically controversial, but we are not concerned with theology. Our aim is to review the empirical evidence for the efficacy of prayer as a treatment for ill-health rather than to consider questions of metaphysics. We judge ourselves bound to analyse the results of any trial that fits our original criteria (including our initial definition of prayer) and which is methodologically well constructed. Having set our protocol we are convinced that it would be unscientific to modify it to exclude a study that fits our criteria for inclusion.”

This is dogmatic cookbook “science” at its worst. People are obliged to think even when they have a protocol. Otherwise, it is not science.

The review authors claimed they had found no evidence that the study was a jest. This is also false. The author of the retroactive prayer study explained it was a jest,[5] and we noted in our comments that we got the same answer when we contacted the author.

It is a scandal that Cochrane has not withdrawn this ridiculous review, which is a pillar of shame for Cochrane.

[1] Roberts L, Ahmed I, Hall S. Intercessory prayer for the alleviation of ill health. Cochrane Database Syst Rev 2007;1:CD000368.

[2] Jørgensen KJ, Hróbjartsson A, Gøtzsche PC. Divine intervention? A Cochrane review on intercessory prayer gone beyond science and reason. J Negat Results Biomed 2009;8:7.

[3] Olshansky B, Dossey L. Retroactive prayer: a preposterous hypothesis? BMJ 2003;327:1465-8.

[4] Bishop JP, Stenger VJ. Retroactive prayer: lots of history, not much mystery, and no science. BMJ 2004;329:1444-6.

[5] Leibovici L. Author’s reply to effects of remote, retroactive intercessory prayer on outcomes in patients with bloodstream infection: randomised controlled trial. BMJ 2002;324:1037.

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