The Study That Circulated for Twenty Years

Randolph Byrd was a cardiologist at San Francisco General Hospital who randomised patients admitted to the coronary care unit into two groups, passing the first names and diagnoses of one group to intercessors elsewhere who prayed for them daily, and leaving the second group unprayed for. Neither the patients nor the hospital staff knew who was in which group. He then compared the two on a long list of clinical outcomes and on a composite score of his own construction that graded each patient's course as good, intermediate or bad. The prayed-for group came out better on that composite.

The paper appeared in the Southern Medical Journal in 1988 and became, for the next two decades, the single most cited piece of evidence in popular argument that prayer has measurable medical effects, quoted in books, sermons and news coverage far more often than it was read. Its actual claims were modest, and Byrd himself did not overstate them in print, but the paper's afterlife in secondhand citation was another matter entirely. The same background-prayer problem applies here and Byrd acknowledged it: patients in a coronary care unit generally have families, and no trial can arrange for a control group that nobody prays for. What a trial can do is compare more organised prayer against less, which is a narrower question than the one the study is usually cited as answering, and one worth keeping in view whenever any result in this literature is quoted.