I clicked on the first link on that Google search, which brought up this paper:
It is a meta-review which has the following abstract:
Background: The use of alternative treatments for illness is common in the United States. Practitioners of these interventions find them compatible with personal philosophies. Consequently, distant intercessory prayer (IP) for healing is one of the most commonly practiced alternative interventions and has recently become the topic of scientific scrutiny.
Purpose: This study was designed to provide a current meta-analytic review of the effects of IP and to assess the impact of potential moderator variables.
Methods: A random effects model was adopted. Outcomes across dependent measures within each study were pooled to arrive at one omnibus effect size. These were combined to generate the overall effect size. A test of homogeneity and examination of several potential moderator variables was conducted.
Results: Fourteen studies were included in the meta-analysis yielding an overall effect size of g = .100 that did not differ from zero. When one controversial study was removed, the effect size reduced to g = .012. No moderator variables significantly influenced results.
Conclusions: There is no scientifically discernable effect for IP as assessed in controlled studies. Given that the IP literature lacks a theoretical or theological base and has failed to produce significant findings in controlled trials, we recommend that further resources not be allocated to this line of research.
The reference to “lack of a theological base” for IP research raised my eyebrows. What did the authors mean by that? I looked up the reference cited in the Conclusion, and it leads to an earlier paper by the first author (Kevin Masters, who is apparently an expert on research on psychology and religion):
The final section is worth quoting almost in full, as it expresses more completely what I’ve been getting at in this thread:
Wrong Method to Address the Question
Christians, and other people of faith, have since the beginning of time offered up prayers for the sick with the fervent belief that, at least on some occasions, these prayers are answered with healing. In the scientific tradition, as far back as 1883 Sir Francis Galton (as cited in Palmer et al., 2004) suggested that whether sick persons who are prayed for recovered more rapidly than those not prayed for was a proper topic for empirical study. Since the scientific method has proven its worth in terms of collecting data about the workings of the world, why not use it to test whether there is evidence to support these long held beliefs?
It is my contention, however, that a major source of confusion in IP studies is the result of applying the wrong method to the question of the efficacy of IP. The scientific method is not appropriate or equipped to resolve questions that concern the intervention of deity which is, I believe, the implicit, ill-defined, and sometimes denied “theory” behind IP research. The basic premise of science is the functioning of a mechanistic and predictable world but the basic premise of the Biblical deity is that God acts according to God’s own purposes and is not constrained by physical limits. God is metaphysical, science is physical. Natural processes are the proper domain of science but supernatural processes are the domain of theology. Further, God indicates that God’s ways are not known to humans nor should they be questioned or tested (Romans 8:26-9:33; 11:33-36). There is no theological principle to suggest that God’s ability to heal can ever be tested by controlled, scientific methods. In fact, quite the opposite seems to be the case. Scriptural passages warn to not tempt, test, or question God (Deuteronomy 6:16; Matthew 4:1-11; Luke 4:1-13).
This confusion over the natural vs. supernatural is inadvertently evident in the limitations section of the Palmer et al. (2004) study. They indicated that their study was limited by the fact that the participants were largely well educated and white, and therefore generalizability was limited. Clearly this would be the case were they studying natural mechanisms that may be influenced by one’s level of education or ethnicity status. But how would prayer fit into this scheme? What mechanism associated with prayer to God suggests that differences in ethnicity or education are moderating variables of prayer’s effectiveness? Is God likely to be influenced in some manner more or less by individuals who vary in their level of education or are of a different ethnic identification? God does not respect one person more than another (Acts 10:34).
Some may argue, as do Harris and colleagues (1999) and more recently Palmer et al. (2004), that imputation of interpretations for this research that incorporate God are not necessary and go beyond what the studies assess. These authors claim that only the natural properties of prayer as it relates to healing are under consideration and therefore the studies are perfectly congruent with scientific principles and assumptions. They further point out that researchers need to be open to testing heretofore undiscovered or unexplained processes. If only natural processes were under study, I completely agree. In fact, reference to God is not necessary and is not made in studies of distant healing, energy fields or energy medicine, etc. But such is clearly not the case in the extant IP literature. The evidence points to an agenda that invokes God into the process.
In other words, scientific research of any kind (including IP research) needs to have some theoretical basis. Otherwise the hypothesis is useless. But the simplistic theoretical hypothesis that “If person A prays for outcome X, then outcome X should be more likely” is not supported even by Christian theology. Some people in this thread apparently think that’s a completely legitimate thing to expect of God - sure, everyone is free to think what they want - but most Christians (except maybe for some who believe in prosperity theology, which is definitely not everyone) who have a more nuanced view of prayer would not agree with that at all. This is why we’re back to what I said earlier: Christians and atheists are not going to agree even on the criteria for calculating the probability of God’s existence.