Furthermore, a meta-analysis was conducted pooling 40 studies consisting of 700 astrologers and over 1000 birth charts.

This meta-analysis was based on 20 trials and a cohort of 158 998 patients, of whom 91 % were hypertensive.

Nevertheless, a 2009 systematic review and meta-analysis of trials in people diagnosed with schizophrenia found that less than half ( 41 %) showed any therapeutic response to an antipsychotic, compared to 24 % on placebo, and that there was a decline in treatment response over time, and possibly a bias in which trial results were published.

This meta-analysis found that long-term use of benzodiazepines was associated with moderate to large adverse effects on all areas of cognition, with visuospatial memory being the most commonly detected impairment.

The study used meta-analysis of over a hundred secondary studies to find some level of effectiveness that was either " proven " or " presumed " to exist.

In 2003, a meta-analysis of the efficacy of hypnotherapy was published by two researchers from the university of Konstanz in Germany, Flammer and Bongartz.

In the 1990s, a growing body of empirical research in I – O psychology was influential in the application of meta-analysis, particularly in the area of the stability of research findings across contexts.

A meta-analysis of selection methods in personnel psychology found that general mental ability was the best overall predictor of job performance and training performance.

The most recent meta-analysis on psychokinesis was published in Psychological Bulletin, along with several critical commentaries.

In a meta-analysis of these experiments published in the British Journal of Psychology in 2004, researchers found that there was a small but significant overall DMILS effect.

A 2003 meta-analysis of randomized clinical trials found that spinal manipulation was " more effective than sham therapy but was no more or less effective than general practitioner care, analgesics, physical therapy, exercise, or back school " in the treatment of low back pain.

Although O ' Rourke suggests that the first meta-analysis was a paper by Karl Pearson in the BMJ in 1904, in reality Pearson computed a simple average in this study and therefore it cannot be considered a meta-analysis.

Although meta-analysis is widely used in epidemiology and evidence-based medicine today, a meta-analysis of a medical treatment was not published until 1955.

The term " meta-analysis " was coined by Gene V. Glass, who was the first modern statistician to formalize the use the term meta-analysis.

The statistical theory surrounding meta-analysis was greatly advanced by the work of Nambury S. Raju, Larry V. Hedges, Harris Cooper, Ingram Olkin, John E. Hunter, Jacob Cohen, Thomas C. Chalmers, Robert Rosenthal and Frank L. Schmidt.

In a 2005 meta-analysis and systematic review of six randomized controlled trials of osteopathic manipulative treatment ( OMT ) that involved blinded assessments of lower back pain in ambulatory settings, it was concluded that OMT significantly reduces low back pain, and that the level of pain reduction is greater than expected from placebo effects alone and persists for at least three months.

This 34 % hit rate was statistically similar to the 37 % hit rate of the 1985 meta-analysis.

This meta-analysis was criticised for including all ganzfeld experiments, regardless of the methods being used.

According to a meta-analysis of prospective studies by the Cochrane Collaboration, the appearance of water-soluble contrast in the cecum on an abdominal radiograph within 24 hours of oral administration predicts resolution of an adhesive small bowel obstruction with a pooled sensitivity of 96 % and specificity of 96 %.

In contrast, a 2008 meta-analysis found no significant overall association between the 5-HTTLPR polymorphism and autism.

A meta-analysis of six randomized controlled trials found no difference between the main diet types ( low calorie, low carbohydrate, and low fat ), with a 2 – 4 kilogram weight loss in all studies.

Several decades after Pearson's work with early versions of meta-analysis, Glass published the first application of modern meta-analytic techniques and triggered their broad application across the social and biomedical sciences.

Personality and attitudinal effects have shown greater predictability, with meta-analysis of parapsychological databases showing the sheep-goat effect, and other traits, to have significant and reliable effects over the accumulated data.

A 1996 meta-analysis studying hypnosis combined with cognitive-behavioural therapy found that people using both treatments lost more weight than people using CBT alone.

Critics say that analogous problems with meta-analysis have been documented in medicine, where it has been shown different investigators performing meta-analyses of the same set of studies have reached contradictory conclusions.

Higher quality for complex tasks costs higher effort, reduced duration for simpler tasks comes with noticeably lower quality – the meta-analysis " suggests that pair programming is not uniformly beneficial or effective ".

" This finding tended to confirm an earlier meta-analysis of the nutritional effects of saturated fat in The American Journal of Clinical Nutrition which found " rospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of coronary heart disease or cardiovascular disease.

Similarly, a meta-analysis of five studies of group psychotherapy for adult sexual abuse survivors showed moderate to strong effect sizes, and there is also good evidence for effectiveness with chronic traumatic stress in war veterans.

Current supplemental guidelines recommend doses of phytosterols in the 1. 6-3. 0 grams per day range ( Health Canada, EFSA, ATP III, FDA ) with a recent meta-analysis demonstrating an 8. 8 % reduction in LDL-cholesterol at a mean dose of 2. 15 gram per day.

One randomized controlled trial found that self-monitoring of blood glucose did not improve the HbA1c among " reasonably well controlled non-insulin treated patients with type 2 diabetes ". A recent meta-analysis of 47 randomized controlled trials encompassing 7677 patients showed that self-care management intervention improves glycemic control in Diabetics, with an estimated 0. 36 % ( 95 % CI, 0. 21-0. 51 ) reduction in their glycosylated Hemoglobin values .< ref > Minet, L., Moller, S., Vach, W., Wagner, L., & Henriksen, J. E. ( 2010 ).

* MIX 2. 0 Professional Excel addin with Ribbon interface for meta-analysis and effect size conversions in Excel ( free and commercial versions ).

A 2001 meta-analysis of clinical trials with placebo groups and no-treatment groups found no evidence for a placebo effect on objectively measured outcomes and possible small benefits in studies with continuous subjective outcomes ( particularly pain ).

According to a meta-analysis of 12 new-generation antidepressants, sertraline and escitalopram are the best in terms of efficacy and acceptability in the acute-phase treatment of adults with unipolar major depression.

A recent meta-analysis showed that EGDT provides a benefit on mortality in patients with sepsis.

In 2007, though, a meta-analysis of 23 statin treatment arms with 309, 506 person-years of follow-up found the risk of cancer was significantly associated with lower achieved LDL-C levels ; the authors said this requires further investigation.

In a meta-analysis of 31 studies, Cosgrove et al .,< ref > concluded that MRSA bacteremia is associated with increased mortality as compared with MSSA bacteremia ( odds ratio

However, this meta-analysis included two large studies of smokers, so it is not clear that the results apply to the general population.

Explores two contrasting views: does meta-analysis provide " objective, quantitative methods for combining evidence from separate but similar studies " or merely " statistical tricks which make unjustified assumptions in producing oversimplified generalisations out of a complex of disparate studies "?

At least two narrative reviews and one meta-analysis of knowledge gap hypothesis research exist.

According to a meta-analysis in the Cochrane Collaboration, two large trials in Russia and Shanghai found no beneficial effects of screening by breast self-examination " but do suggest increased harm in terms of increased numbers of benign lesions identified and an increased number of biopsies performed.

An updated meta-analysis including these trials found that saw palmetto extract " was not more effective than placebo for treatment of hyperplasia but following two million U. S. who use saw palmetto, urinary problems are greatly reduced.

The paper was a follow-up and expansion of a 1997 meta-analysis by two of the paper's three authors.

's ( 1998 ) meta-analysis, Heather Marie Ulrich, with two colleagues, replicated the study in The Scientific Review of Mental Health Practice and confirmed its main findings.

However, in a meta-analysis of the current research, De Drue and Weingart ( 2003 ) showed that these two concepts are related to each other ( corrected correlation, ρ =. 54 ).

A meta-analysis of 14 randomized, controlled trials comparing plant sterols to plant stanols directly at doses of 0. 6 to 2. 5 g / day showed no difference between the two forms on total cholesterol, LDL cholesterol, HDL cholesterol, or triglyceride levels.

To make sense out of this, there is a statistical technique called meta-analysis that averages the results of two or more studies to see if the effect of an independent variable is reliable.

A large meta-analysis from Johns Hopkins University published in Neurosurgery concluded that " there is no clear consensus in these two studies or in the 45 observational studies included.