of view of the Sun' [...]". Prayer healing Prayer is often used as a means of faith healing in an attempt to use religious or spiritual means to prevent illness, cure disease, or improve health. Scientific studies regarding the use of prayer have mostly concentrated on its effect on the healing of sick or injured people. Meta-studies have been performed showing evidence only for no effect or a potentially small effect. For instance, a 2006 meta analysis on 14 studies concluded that there is "no discernable effect" while a 2007 systemic review of studies on intercessory prayer reported inconclusive results, noting that seven of 17 studies had "small, but significant, effect sizes" but the review noted that the most methodologically rigorous studies failed to produce significant findings. Some studies have indicated increased medical complications in groups receiving prayer over those without. The efficacy of petition in prayer for physical healing to a deity has been evaluated in numerous other studies, with contradictory results. There has been some criticism of the way the studies were conducted. Some attempt to heal by prayer, mental practices, spiritual insights, or other techniques, claiming they can summon divine or supernatural intervention on behalf of the ill. Others advocate that ill people may achieve healing through prayer performed by themselves. According to the varied beliefs of those who practice it, faith healing may be said to afford gradual relief from pain or sickness or to bring about a sudden "miracle cure", and it may be used in place of, or in tandem with, conventional medical techniques for alleviating or curing diseases. Faith healing has been criticized on the grounds that those who use it may delay seeking potentially curative conventional medical care. This is particularly problematic when parents use faith healing techniques on children. Efficacy of prayer healing In 1872, Francis Galton conducted a famous statistical experiment to determine whether prayer had a physical effect on the external environment. Galton hypothesized that if prayer was effective, members of the British Royal family would live longer, given that thousands prayed for their wellbeing every Sunday. He therefore compared longevity in the British Royal family with that of the general population, and found no difference. While the experiment was probably intended to satirize, and suffered from a number of confounders, it set the precedent for a number of different studies, the results of which are contradictory. Two studies