The largest-ever study of prayer offers nothing but discouragement to religious believers hoping for evidence that prayer for God's intervention in the natural order is effective. The study of third-party prayer, also known as intercessory prayer, says that praying for the health of patients from a distance is not effective in reducing complications after heart surgery.

The $2.4 million Study of the Therapeutic Effects of Intercessory Prayer, or STEP, is the sixth and most expensive study to find that intercessory prayer has no real effect on the wellbeing of patients. The nine-year research project was partly supported by the John Templeton Foundation, which also funds Science & Theology News.

Another important yet unexpected and even disturbing finding of STEP is that the group of heart patients who knew they were receiving prayers from strangers did not do as well as those who didn't know.

The study used a sample of 1,802 bypass patients from six hospitals who were randomly assigned to one of three groups: Group 1 received intercessory prayer after being told they may or may not receive it, Group 2 did not receive intercessory prayers after being told they may or may not receive it, and Group 3 were told they would be receiving intercessory prayer and did receive it. STEP findings are scheduled to appear in the April issue of American Heart Journal.

"Those receiving blinded prayer fared the same as those who were not prayed for," said Dr. Charles F. Bethea, principal investigator at the Integris Baptist Medical Center in Oklahoma City, Okla. "Paradoxically, those who were indeed aware that prayer was being provided to them actually fared worse," he said.

Methodology may be the issue behind the unusual Group 3 result. The STEP researchers speculated that perhaps the introduction of the prayer protocol itself — confiding in some that they were selected for prayer, for instance — might have induced a form of performance anxiety or made the patients feel doubtful about their outcome.

"One line we considered in this study was did the patient think 'am I so sick that they had to call in the prayer team?'," said Bethea.

Another question is the subjects themselves. "I wonder how free enrollees were in our study to say no to being prayed for, especially when asked by a caregiver at such a crucial time," said the Rev. Dean Marek, director of chaplain services at the Mayo Clinic in Rochester, Minn.

With these types of unresolved issues, investigators said that it is possible that intercessory prayer may not be amenable to randomized control methodology and that a large-scale study like this may not be replicated.

Marek also pointed to the problem with conducting studies on prayer that reduce it to a replicable commodity — because the effect of prayer can't be replicated. But a study such as STEP can yield other benefits. "I hope this leads to some further discussion as to the nature and relevance and power of this thing we call prayer," he said.