Methods to calculate uncertainty in the estimated overall effect size from a random‐effects meta‐analysis

Several pharmacogenetic tests to support drug selection in psychiatric patients have recently become available. The current meta-analysis aimed to assess the clinical utility of a commercial pharmacogenetic-based tool for psychiatry (Neuropharmagen®) in the treatment management of depressive patients. Random-effects meta-analysis of clinical studies that had examined the effect of this tool on the improvement of depressive patients was performed. Effects were summarized as standardized differences between treatment groups. A total of 450 eligible subjects from three clinical studies were examined. The random effects model estimated a statistically significant effect size for the pharmacogenetic-guided prescription (d = 0.34, 95% CI = 0.11–0.56, p-value = 0.004), which corresponded to approximately a 1.8-fold increase in the odds of clinical response for pharmacogenetic-guided vs. unguided drug selection. After exclusion of patients with mild depression, the pooled estimated effect size increased to 0.42 (95% CI = 0.19–0.65, p-value = 0.004, n = 287), corresponding to an OR = 2.14 (95% CI = 1.40–3.27). These results support the clinical utility of this pharmacogenetic-based tool in the improvement of health outcomes in patients with depression, especially those with moderate–severe depression. Additional pragmatic RCTs are warranted to consolidate these findings in other patient populations.

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Nutraceutical supplements in management of pain and disability in osteoarthritis: a systematic review and meta-analysis of randomized clinical trials

Scientific Reports ◽

10.1038/s41598-020-78075-x ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Dawood Aghamohammadi ◽

Neda Dolatkhah ◽

Fahimeh Bakhtiari ◽

Fariba Eslamian ◽

Maryam Hashemian

Keyword(s):

Pain Intensity ◽

Physical Function ◽

Random Effects ◽

Effect Size ◽

Meta Analysis ◽

Effect Sizes ◽

Cochrane Library ◽

Random Effects Model ◽

Womac Index ◽

Pain Subscale

AbstractThis study designed to evaluate the effect of nutraceutical supplementation on pain intensity and physical function in patients with knee/hip OA. The MEDLINE, Web of Science, Cochrane Library, Scopus, EMBASE, Google Scholar, Science direct, and ProQuest in addition to SID, Magiran, and Iranmedex were searched up to March 2020. Records (n = 465) were screened via the PICOS criteria: participants were patients with hip or knee OA; intervention was different nutritional supplements; comparator was any comparator; the outcome was pain intensity (Visual analogue scale [VAS]) and physical function (Western Ontario and McMaster Universities Arthritis [WOMAC] index); study type was randomized controlled trials. The random effects model was used to pool the calculated effect sizes. The standardized mean difference (SMD) of the outcome changes was considered as the effect size. The random effects model was used to combine the effect sizes. Heterogeneity between studies was assessed by Cochran's (Q) and I2 statistics. A total of 42 RCTs were involved in the meta-analysis. Nutritional supplementation were found to improve total WOMAC index (SMD = − 0.23, 95% CI − 0.37 to − 0.08), WOMAC pain (SMD = − 0.36, 95% CI − 0.62 to − 0.10) and WOMAC stiffness (SMD = − 0.47, 95% CI − 0.71 to − 0.23) subscales and VAS (SMD = − 0.79, 95% CI − 1.05 to − 0.05). Results of subgroup analysis according to the supplementation duration showed that the pooled effect size in studies with < 10 months, 10–20 months and > 20 months supplementation duration were 0.05, 0.27, and 0.36, respectively for WOMAC total score, 0.14, 0.55 and 0.05, respectively for WOAMC pain subscale, 0.59, 0.47 and 0.41, respectively for WOMAC stiffness subscale, 0.05, 0.57 and 0.53, respectively for WOMAC physical function subscale and 0.65, 0.99 and 0.12, respectively for VAS pain. The result suggested that nutraceutical supplementation of patients with knee/hip OA may lead to an improvement in pain intensity and physical function.

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Confidence intervals for the overall effect size in random-effects meta-analysis.

Psychological Methods ◽

10.1037/1082-989x.13.1.31 ◽

2008 ◽

Vol 13 (1) ◽

pp. 31-48 ◽

Cited By ~ 104

Author(s):

Julio Sánchez-Meca ◽

Fulgencio Marín-Martínez

Keyword(s):

Confidence Intervals ◽

Random Effects ◽

Effect Size ◽

Meta Analysis

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Detecting and correcting for publication bias in meta-analysis – A truncated normal distribution approach

Statistical Methods in Medical Research ◽

10.1177/0962280216684671 ◽

2016 ◽

Vol 27 (9) ◽

pp. 2722-2741 ◽

Cited By ~ 4

Author(s):

Qiaohao Zhu ◽

KC Carriere

Keyword(s):

Normal Distribution ◽

Publication Bias ◽

Random Effects ◽

Effect Size ◽

Meta Analysis ◽

Truncated Normal Distribution ◽

Random Effects Models ◽

Funnel Plot ◽

Fixed And Random Effects ◽

Truncated Normal

Publication bias can significantly limit the validity of meta-analysis when trying to draw conclusion about a research question from independent studies. Most research on detection and correction for publication bias in meta-analysis focus mainly on funnel plot-based methodologies or selection models. In this paper, we formulate publication bias as a truncated distribution problem, and propose new parametric solutions. We develop methodologies of estimating the underlying overall effect size and the severity of publication bias. We distinguish the two major situations, in which publication bias may be induced by: (1) small effect size or (2) large p-value. We consider both fixed and random effects models, and derive estimators for the overall mean and the truncation proportion. These estimators will be obtained using maximum likelihood estimation and method of moments under fixed- and random-effects models, respectively. We carried out extensive simulation studies to evaluate the performance of our methodology, and to compare with the non-parametric Trim and Fill method based on funnel plot. We find that our methods based on truncated normal distribution perform consistently well, both in detecting and correcting publication bias under various situations.

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Effects of Participation on Performance and Satisfaction: Additional Meta-Analytic Evidence

Psychological Reports ◽

10.2466/pr0.1999.84.3.719 ◽

1999 ◽

Vol 84 (3) ◽

pp. 719-725 ◽

Cited By ~ 9

Author(s):

John A. Wagner ◽

Jeffrey A. LePine

Keyword(s):

Random Effects ◽

Effect Size ◽

Meta Analysis ◽

Research Literature ◽

Previous Literature ◽

Literature Reviews ◽

Different Types ◽

Recent Debate ◽

And Performance

Stimulated by recent debate, this study investigated whether prior research supports the statement that different forms of participation have different effects on performance and satisfaction in the workplace. Using a collection of 75 correlations drawn from published analyses, a meta-analysis using random effects procedures indicated that relationships between participation and performance reported in the research literature are similar in size and direction across different types of participation. Meta-analytic results also indicated similarity in the size and direction of relationships between participation and satisfaction across different forms of participation and suggested that effect size statistics published in research on participation and performance are generally similar to those reported in studies of participation and satisfaction. These findings differ from the results of another recent meta-analysis and from those of several previous literature reviews but support the primary conclusions of an earlier meta-analytic assessment.

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The effect of cooperative learning on academic achievement: A meta-analysis on the relationship between the study group size and effect size İşbirlikli öğrenmenin başarıya etkisi: Çalışma grubu ile etki büyüklüğü arasındaki ilişkiye dair bir meta analiz çalışması

Journal of Human Sciences ◽

10.14687/jhs.v14i1.4314 ◽

2017 ◽

Vol 14 (1) ◽

pp. 473 ◽

Cited By ~ 1

Author(s):

Murat Tuncer ◽

Melih Dikmen

Keyword(s):

Cooperative Learning ◽

Random Effects ◽

Effect Size ◽

Fixed Effects ◽

Meta Analysis ◽

Experimental Studies ◽

Study Group ◽

Random Effects Model ◽

Learning Groups ◽

The Relationship

The purpose of this study was to determine the effect of cooperative learning on achievement and the relationship between the study group and effect size by means of meta-analysis. Meta-analysis is the method employed in order to statistically analyze the quantitative data collected in independent and multiple studies carried out on similar topics, and to reach a general judgment regarding the results of these studies. Certain criteria were used in order to decide which researches would be included in the meta-analysis. Based on these criteria, it was decided to include 6 experimental studies in the meta-analysis. As a result, for the six studies, the effect size calculated within 95 % confidence interval has proved to be .518 based on random effects model. When two studies with the largest learning groups are excluded from the research respectively, firstly this effect size increases to .528, later it is calculated as .817 without any model discrimination. When effect size intervals in literature (≥ 0.5: strong, ≥ 0.3: moderate and ≥ .01 weak) is taken into consideration, the effect of cooperative learning on achievement has been observed as “Strong”. In addition to this, contrary to some views in literature, it has been seen that large learning groups have higher standard errors and a bigger effect size has been achieved when such studies have been excluded from the analysis. What is more, even the limitation of fixed effects model has disappeared, and the effect size calculated in fixed effects and random effects model has been balanced. ÖzetBu araştırmanın amacı, işbirlikli öğrenmenin başarı üzerindeki etkisini ve çalışma grubu ile etki büyüklüğü arasındaki ilişkiyi meta-analiz yöntemiyle belirlemektir. Meta-analiz, benzer konularda yapılmış birbirinden bağımsız ve çok sayıda çalışmadan elde edilmiş sayısal verileri istatistiksel olarak analiz etme ve bu çalışmaların sonuçları hakkında genel bir yargıya varma yöntemidir. Hangi araştırmaların meta-analize dâhil edileceğine yönelik seçimlerin yapılmasında belirli ölçütler kullanılmıştır. Bu ölçütlere dayalı olarak 6 adet deneysel araştırmanın meta-analize dâhil edilmesine karar verilmiştir. Sonuç olarak; altı çalışma için %95 güven aralığında hesaplanan etki büyüklüğü rastgele etkiler modeline göre .518’dir. En büyük çalışma grubuna sahip iki araştırma sırasıyla araştırma dışında tutulduğunda bu etki büyüklüğü önce .528’ e çıkmakta, sonrasında ise model ayrımı olmaksızın .817 olarak hesaplanmaktadır. Alan yazındaki etki büyüklüğü aralıkları (≥ 0.5: güçlü, ≥ 0.3: orta düzey ve ≥ .01 zayıf) dikkate alındığında işbirlikli öğrenmenin başarı üzerindeki etkisi “Güçlü” bir etki olarak gözlenmiştir. Ayrıca alan yazındaki bazı görüşlerin aksine büyük çalışma gruplarının standart hatalarının daha yüksek olduğu, bu araştırmaların analiz dışında tutulması ile daha büyük etki büyüklüklerine ulaşıldığı, hatta sabit etki modelinin sınırlılığının bile ortadan kalktığı, sabit etki ve rastgele etki modelinde hesaplanan etki büyüklüğünün eşitlendiği görülmüştür.

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A meta-analysis on parochial cooperation among children and adolescents

10.31234/osf.io/uexmr ◽

2020 ◽

Author(s):

Aleksandra Lazić ◽

Danka Purić ◽

Ksenija Krstic

Keyword(s):

Decision Making ◽

Children And Adolescents ◽

Experimental Economics ◽

Random Effects ◽

Effect Size ◽

Meta Analysis ◽

Random Effects Model ◽

Personal Cost ◽

Cooperative Decision Making ◽

Economics Research

This meta-analysis integrated findings from a recent upsurge of economic experiments (2008–2019) exploring parochialism in cooperative decision-making of children and adolescents. Based on 20 studies (k = 69, N = 5268, age = 3–19 years), a random-effects model revealed a small overall effect size indicating that children and adolescents were more willing to incur a personal cost to benefit ingroups, compared to outgroups (d = 0.17). A series of single-moderator analyses tested boundary conditions of this tendency. The implications for the methodologies currently used in experimental economics research are discussed.

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Improving the accuracy of likelihood-based inference in meta-analysis and meta-regression

Biometrika ◽

10.1093/biomet/asx001 ◽

2017 ◽

Vol 104 (2) ◽

pp. 489-496 ◽

Cited By ~ 6

Author(s):

I. Kosmidis ◽

A. Guolo ◽

C. Varin

Keyword(s):

Random Effects ◽

Effect Size ◽

Variance Component ◽

General Framework ◽

Meta Analysis ◽

Asymptotic Bias ◽

Likelihood Estimator ◽

Random Effects Models ◽

The Mean ◽

Meta Regression

Summary Random-effects models are frequently used to synthesize information from different studies in meta-analysis. While likelihood-based inference is attractive both in terms of limiting properties and of implementation, its application in random-effects meta-analysis may result in misleading conclusions, especially when the number of studies is small to moderate. The current paper shows how methodology that reduces the asymptotic bias of the maximum likelihood estimator of the variance component can also substantially improve inference about the mean effect size. The results are derived for the more general framework of random-effects meta-regression, which allows the mean effect size to vary with study-specific covariates.

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Meta-Analysis of Sensorimotor Gating Deficits in Patients With Schizophrenia Evaluated by Prepulse Inhibition Test

Schizophrenia Bulletin ◽

10.1093/schbul/sbaa059 ◽

2020 ◽

Vol 46 (6) ◽

pp. 1482-1497

Author(s):

Rodrigo San-Martin ◽

Leonardo Andrade Castro ◽

Paulo Rossi Menezes ◽

Francisco José Fraga ◽

Priscyla Waleska Simões ◽

...

Keyword(s):

Prepulse Inhibition ◽

Random Effects ◽

Effect Size ◽

Meta Analysis ◽

Sensorimotor Gating ◽

Control Group ◽

Random Effects Models ◽

Meta Regression Analysis ◽

High Level ◽

Meta Analyses

Abstracts Prepulse inhibition (PPI) of startle is an operational measure of sensorimotor gating that is often impaired in patients with schizophrenia. Despite the large number of studies, there is considerable variation in PPI outcomes reported. We conducted a systematic review and meta-analysis investigating PPI impairment in patients with schizophrenia compared with healthy control subjects, and examined possible explanations for the variation in results between studies. Major databases were screened for observational studies comparing healthy subjects and patients with schizophrenia for the prepulse and pulse intervals of 60 and 120 ms as primary outcomes, ie, PPI-60 and PPI-120. Standardized mean difference (SMD) and 95% confidence intervals (CI) were extracted and pooled using random effects models. We then estimated the mean effect size of these measures with random effects meta-analyses and evaluated potential PPI heterogeneity moderators, using sensitivity analysis and meta-regressions. Sixty-seven primary studies were identified, with 3685 healthy and 4290 patients with schizophrenia. The schizophrenia group showed reduction in sensorimotor gating for both PPI-60 (SMD = −0.50, 95% CI = [−0.61, −0.39]) and PPI-120 (SMD = −0.44, 95% CI = [−0.54, −0.33]). The sensitivity and meta-regression analysis showed that sample size, gender proportion, imbalance for gender, source of control group, and study continent were sources of heterogeneity (P < .05) for both PPI-60 and PPI-120 outcomes. Our findings confirm a global sensorimotor gating deficit in schizophrenia patients, with overall moderate effect size for PPI-60 and PPI-120. Methodological consistency should decrease the high level of heterogeneity of PPI results between studies.

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Combined Effects of Aerobic Exercise and Diet on Lipids and Lipoproteins in Overweight and Obese Adults: A Meta-Analysis

Journal of Obesity ◽

10.1155/2012/985902 ◽

2012 ◽

Vol 2012 ◽

pp. 1-16 ◽

Cited By ~ 11

Author(s):

George A. Kelley ◽

Kristi S. Kelley ◽

Susan Roberts ◽

William Haskell

Keyword(s):

Aerobic Exercise ◽

Random Effects ◽

Effect Size ◽

Meta Analysis ◽

Combined Effects ◽

Obese Adults ◽

Men And Women ◽

Random Effects Models ◽

Multiple Groups ◽

Lipids And Lipoproteins

This study used the aggregate data meta-analytic approach to determine the combined effects of aerobic exercise and diet on lipids and lipoproteins in overweight and obese adults. Twelve studies representing 859 men and women (443 intervention, 416 control) were included. Using random-effects models, statistically significant, intervention minus control reductions were found for TC (−12.8 mg/dL, 95% CI, −19.9 to −5.7), TC : HDL-C (−0.5 mg/dL, 95% CI, −0.8 to −0.1), LDL-C (−6.8 mg/dL, 95% CI, −11.8 to −1.8), and TG (−13.1 mg/dL, 95% CI, −21.2 to −5.0) but not HDL-C (−0.4 mg/dL, 95% CI, −2.3 to 1.6). Results remained robust when adjusted for publication bias, deleting each study from the model once, and collapsing results for multiple groups from the same study into one effect size. These findings suggest that concurrent aerobic exercise and diet improve TC, LDL-C, TC : HDL-C, and TG, but not HDL-C, in overweight and obese adults.

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