Has a study been done on the "Power of Prayer"? Has a controlled, scientific study of the "Power of Prayer", ever been performed? Can one, or two, of the results be breafly explained?
Yes, at least for intercessory prayer. In 2005, the John Templeton Foundation conducted a carefully designed, double-blind trial of the effect of intercessory prayer on the outcome of surgery. The intention was to evaluate whether (1) receiving intercessory prayer or (2) being certain of receiving intercessory prayer was associated with uncomplicated recovery after coronary artery bypass graft (CABG) surgery. It was felt that previous trials showing a benefit had used sub-optimal methods of data analysis, non-standard methods of randomisation and allocation concealment, and untested outcome measures, while those showing no effect had insufficient statistical power to reach this conclusion.  

Patients were enrolled between January 1998 and November 2000. Of 3,295 eligible patients, 1,493 did not wish to participate and 1,802 patients enrolled (Oklahoma–548; Massachusetts–492; Washington DC–284; Tennessee–256; Minnesota–200; Florida–22) (Figure 1). Intercessory prayer was provided according to the protocol to 1,192/1,205 (99%) of patients randomized to Group 1 and Group 3, over the course of the study period (1,046 days). The overall daily mean of intercessors was 33 (range 10–58). Intercessors reported praying from 30 seconds to several hours, from 1 to 4 times per day.

The study had 2 main findings. First, intercessory prayer itself had no effect on whether complications occurred after CABG. Second, patients who were certain that intercessors would pray for them had a higher rate of complications than patients who were uncertain but did receive intercessory prayer. It is suggested this anomaly may have resulted from anxiety that resulted from knowing that others were praying.