Random-Effects Model | |||||||||||||
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Estimate | se | Z | p | CI Lower Bound | CI Upper Bound | ||||||||
. | . | . | . | . | . | . | |||||||
. | . | . | . | . | . | . | |||||||
[3] |
Heterogeneity Statistics | |||||||||||||||
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Tau | Tau² | I² | H² | R² | df | Q | p | ||||||||
. | . | . | . | . | . | . | . | ||||||||
Model Fit Statistics and Information Criteria | |||||||||||
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log-likelihood | Deviance | AIC | BIC | AICc | |||||||
. | . | . | . | . | . | ||||||
. | . | . | . | . | . | ||||||
Selection Model Results | |||||||||
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Estimate | SE | p-value | CI Lower Bound | CI Upper Bound | |||||
. | . | . | . | . | |||||
[3] |
Test Name | value | p | |||
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. | . | . | |||
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. | . | . | |||
Test of Excess Significance | Significant Findings | |||
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. | . | ||
. | . | ||
[0] |
Test of Excess Significance | Estimated Power of Tests | |||||||||
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Min | Q1 | Median | Q3 | Max | |||||
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[0] |
Publication bias test p-uniform | |||
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Test Statistic | p-value | ||
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Effect size estimation p-uniform | |||||||||||
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Effect Size Estimate | CI Lower Bound | CI upper Bound | Z | p-value | Number of Significant Studies | ||||||
. | . | . | . | . | . | ||||||
Two One-Sided Tests Equivalence Testing | |||||||||||||||
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Z-Value Lower Bound | P-Value Lower Bound | Z-Value Upper Bound | P-Value Upper Bound | Lower Limit Confidence Interval TOST | Upper Limit Confidence Interval TOST | LL_CI_ZTEST | Z-Value Upper Limit Confidence Interval TOST | ||||||||
. | . | . | . | . | . | . | . | ||||||||
[0] |
Random-Effects Model | |||||||||||||
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Estimate | se | Z | p | CI Lower Bound | CI Upper Bound | ||||||||
. | . | . | . | . | . | . | |||||||
. | . | . | . | . | . | . | |||||||
[3] |
Heterogeneity Statistics | |||||||||||||||
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Tau | Tau² | I² | H² | R² | df | Q | p | ||||||||
. | . | . | . | . | . | . | . | ||||||||
Model Fit Statistics and Information Criteria | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
log-likelihood | Deviance | AIC | BIC | AICc | |||||||
. | . | . | . | . | . | ||||||
. | . | . | . | . | . | ||||||
Selection Model Results | |||||||||
---|---|---|---|---|---|---|---|---|---|
Estimate | SE | p-value | CI Lower Bound | CI Upper Bound | |||||
. | . | . | . | . | |||||
[3] |
Test Name | value | p | |||
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. | . | . | |||
. | . | . | |||
. | . | . | |||
. | . | . | |||
Test of Excess Significance | Significant Findings | |||
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. | . | ||
. | . | ||
. | . | ||
[0] |
Test of Excess Significance | Estimated Power of Tests | |||||||||
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Min | Q1 | Median | Q3 | Max | |||||
. | . | . | . | . | |||||
[0] |
Publication bias test p-uniform | |||
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Test Statistic | p-value | ||
. | . | ||
Effect size estimation p-uniform | |||||||||||
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Effect Size Estimate | CI Lower Bound | CI upper Bound | Z | p-value | Number of Significant Studies | ||||||
. | . | . | . | . | . | ||||||
Two One-Sided Tests Equivalence Testing | |||||||||||||||
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Z-Value Lower Bound | P-Value Lower Bound | Z-Value Upper Bound | P-Value Upper Bound | Lower Limit Confidence Interval TOST | Upper Limit Confidence Interval TOST | LL_CI_ZTEST | Z-Value Upper Limit Confidence Interval TOST | ||||||||
. | . | . | . | . | . | . | . | ||||||||
[0] |
Random-Effects Model | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Estimate | se | Z | p | CI Lower Bound | CI Upper Bound | ||||||||
. | . | . | . | . | . | . | |||||||
. | . | . | . | . | . | . | |||||||
[3] |
Heterogeneity Statistics | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Tau | Tau² | I² | H² | R² | df | Q | p | ||||||||
. | . | . | . | . | . | . | . | ||||||||
Model Fit Statistics and Information Criteria | |||||||||||
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log-likelihood | Deviance | AIC | BIC | AICc | |||||||
. | . | . | . | . | . | ||||||
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Test Name | value | p | |||
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. | . | . | |||
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. | . | . | |||
Two One-Sided Tests Equivalence Testing | |||||||||||||||
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Z-Value Lower Bound | P-Value Lower Bound | Z-Value Upper Bound | P-Value Upper Bound | LL_CI_TOST | UL_CI_TOST | LL_CI_ZTEST | UL_CI_ZTEST | ||||||||
. | . | . | . | . | . | . | . | ||||||||
[0] |
Random-Effects Model | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Estimate | se | Z | p | CI Lower Bound | CI Upper Bound | ||||||||
. | . | . | . | . | . | . | |||||||
. | . | . | . | . | . | . | |||||||
[3] |
Heterogeneity Statistics | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Tau | Tau² | I² | H² | R² | df | Q | p | ||||||||
. | . | . | . | . | . | . | . | ||||||||
Model Fit Statistics and Information Criteria | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
log-likelihood | Deviance | AIC | BIC | AICc | |||||||
. | . | . | . | . | . | ||||||
. | . | . | . | . | . | ||||||
Selection Model Results | |||||||||
---|---|---|---|---|---|---|---|---|---|
Estimate | SE | p-value | CI Lower Bound | CI Upper Bound | |||||
. | . | . | . | . | |||||
[3] |
Test Name | value | p | |||
---|---|---|---|---|---|
. | . | . | |||
. | . | . | |||
. | . | . | |||
. | . | . | |||
Test of Excess Significance | Significant Findings | |||
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. | . | ||
. | . | ||
[0] |
Test of Excess Significance | Estimated Power of Tests | |||||||||
---|---|---|---|---|---|---|---|---|---|
Min | Q1 | Median | Q3 | Max | |||||
. | . | . | . | . | |||||
[0] |
Publication bias test p-uniform | |||
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Test Statistic | p-value | ||
. | . | ||
Effect size estimation p-uniform | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Effect Size Estimate | CI Lower Bound | CI upper Bound | Z | p-value | Number of Significant Studies | ||||||
. | . | . | . | . | . | ||||||
Two One-Sided Tests Equivalence Testing | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Z-Value Lower Bound | P-Value Lower Bound | Z-Value Upper Bound | P-Value Upper Bound | Lower Limit Confidence Interval TOST | Upper Limit Confidence Interval TOST | LL_CI_ZTEST | Z-Value Upper Limit Confidence Interval TOST | ||||||||
. | . | . | . | . | . | . | . | ||||||||
[0] |
Random-Effects Model | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Estimate | se | Z | p | CI Lower Bound | CI Upper Bound | ||||||||
. | . | . | . | . | . | . | |||||||
. | . | . | . | . | . | . | |||||||
[3] |
Heterogeneity Statistics | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Tau | Tau² | I² | H² | R² | df | Q | p | ||||||||
. | . | . | . | . | . | . | . | ||||||||
Model Fit Statistics and Information Criteria | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
log-likelihood | Deviance | AIC | BIC | AICc | |||||||
. | . | . | . | . | . | ||||||
. | . | . | . | . | . | ||||||
Selection Model Results | |||||||||
---|---|---|---|---|---|---|---|---|---|
Estimate | SE | p-value | CI Lower Bound | CI Upper Bound | |||||
. | . | . | . | . | |||||
[3] |
Test Name | value | p | |||
---|---|---|---|---|---|
. | . | . | |||
. | . | . | |||
. | . | . | |||
. | . | . | |||
Test of Excess Significance | Significant Findings | |||
---|---|---|---|
. | . | ||
. | . | ||
. | . | ||
[0] |
Test of Excess Significance | Estimated Power of Tests | |||||||||
---|---|---|---|---|---|---|---|---|---|
Min | Q1 | Median | Q3 | Max | |||||
. | . | . | . | . | |||||
[0] |
Publication bias test p-uniform | |||
---|---|---|---|
Test Statistic | p-value | ||
. | . | ||
Effect size estimation p-uniform | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Effect Size Estimate | CI Lower Bound | CI upper Bound | Z | p-value | Number of Significant Studies | ||||||
. | . | . | . | . | . | ||||||
Two One-Sided Tests Equivalence Testing | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Z-Value Lower Bound | P-Value Lower Bound | Z-Value Upper Bound | P-Value Upper Bound | Lower Limit Confidence Interval TOST | Upper Limit Confidence Interval TOST | LL_CI_ZTEST | Z-Value Upper Limit Confidence Interval TOST | ||||||||
. | . | . | . | . | . | . | . | ||||||||
[0] |
Random-Effects Model (k = 13) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Estimate | se | Z | p | CI Lower Bound | CI Upper Bound | ||||||||
Intercept | 0.303 | 0.124 | 2.45 | 0.014 | 0.060 | 0.546 | |||||||
. | . | . | . | . | . | ||||||||
Note. Tau² Estimator: Restricted Maximum-Likelihood | |||||||||||||
[3] |
Heterogeneity Statistics | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Tau | Tau² | I² | H² | R² | df | Q | p | ||||||||
0.315 | 0.0989 (SE= 0.0793 ) | 52.36% | 2.099 | . | 12.000 | 25.475 | 0.013 | ||||||||
The analysis was carried out using the standardized mean difference as the outcome measure. A random-effects model was fitted to the data. The amount of heterogeneity (i.e., tau²), was estimated using the restricted maximum-likelihood estimator (Viechtbauer 2005). In addition to the estimate of tau², the Q-test for heterogeneity (Cochran 1954) and the I² statistic are reported. In case any amount of heterogeneity is detected (i.e., tau² > 0, regardless of the results of the Q-test), a prediction interval for the true outcomes is also provided. Studentized residuals and Cook's distances are used to examine whether studies may be outliers and/or influential in the context of the model. Studies with a studentized residual larger than the 100 x (1 - 0.05/(2 X k))th percentile of a standard normal distribution are considered potential outliers (i.e., using a Bonferroni correction with two-sided alpha = 0.05 for k studies included in the meta-analysis). Studies with a Cook's distance larger than the median plus six times the interquartile range of the Cook's distances are considered to be influential. The rank correlation test and the regression test, using the standard error of the observed outcomes as predictor, are used to check for funnel plot asymmetry. A total of k=13 studies were included in the analysis. The observed standardized mean differences ranged from -0.5950 to 0.9007, with the majority of estimates being positive (69%). The estimated average standardized mean difference based on the random-effects model was \hat{\mu} = 0.3033 (95% CI: 0.0605 to 0.5462). Therefore, the average outcome differed significantly from zero (z = 2.4481, p = 0.0144). According to the Q-test, the true outcomes appear to be heterogeneous (Q(12) = 25.4749, p = 0.0127, tau² = 0.0989, I² = 52.3638%). A 95% prediction interval for the true outcomes is given by -0.3591 to 0.9658. Hence, although the average outcome is estimated to be positive, in some studies the true outcome may in fact be negative. An examination of the studentized residuals revealed that none of the studies had a value larger than ± 2.8905 and hence there was no indication of outliers in the context of this model. According to the Cook's distances, none of the studies could be considered to be overly influential. Neither the rank correlation nor the regression test indicated any funnel plot asymmetry (p = 0.2044 and p = 0.0866, respectively).
Publication Bias Assessment | |||||
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Test Name | value | p | |||
Fail-Safe N | 46.000 | < .001 | |||
Begg and Mazumdar Rank Correlation | -0.282 | 0.204 | |||
Egger's Regression | -1.714 | 0.087 | |||
Trim and Fill Number of Studies | 0.000 | . | |||
Note. Fail-safe N Calculation Using the Rosenthal Approach | |||||
Random-Effects Model | |||||||||||||
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Estimate | se | Z | p | CI Lower Bound | CI Upper Bound | ||||||||
. | . | . | . | . | . | . | |||||||
. | . | . | . | . | . | . | |||||||
[3] |
Heterogeneity Statistics | |||||||||||||||
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Tau | Tau² | I² | H² | R² | df | Q | p | ||||||||
. | . | . | . | . | . | . | . | ||||||||
Model Fit Statistics and Information Criteria | |||||||||||
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log-likelihood | Deviance | AIC | BIC | AICc | |||||||
. | . | . | . | . | . | ||||||
. | . | . | . | . | . | ||||||
Selection Model Results | |||||||||
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Estimate | SE | p-value | CI Lower Bound | CI Upper Bound | |||||
. | . | . | . | . | |||||
[3] |
Test Name | value | p | |||
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. | . | . | |||
. | . | . | |||
. | . | . | |||
. | . | . | |||
Test of Excess Significance | Significant Findings | |||
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. | . | ||
. | . | ||
. | . | ||
[4] |
Test of Excess Significance | Estimated Power of Tests | |||||||||
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Min | Q1 | Median | Q3 | Max | |||||
. | . | . | . | . | |||||
[4] |
Publication bias test p-uniform | |||
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Test Statistic | p-value | ||
. | . | ||
Effect size estimation p-uniform | |||||||||||
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Effect Size Estimate | CI Lower Bound | CI upper Bound | Z | p-value | Number of Significant Studies | ||||||
. | . | . | . | . | . | ||||||
Two One-Sided Tests Equivalence Testing | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Z-Value Lower Bound | P-Value Lower Bound | Z-Value Upper Bound | P-Value Upper Bound | Lower Limit Confidence Interval TOST | Upper Limit Confidence Interval TOST | LL_CI_ZTEST | Z-Value Upper Limit Confidence Interval TOST | ||||||||
. | . | . | . | . | . | . | . | ||||||||
[5] |
[1] The jamovi project (2021). jamovi. (Version 2.2) [Computer Software]. Retrieved from https://www.jamovi.org.
[2] R Core Team (2021). R: A Language and environment for statistical computing. (Version 4.0) [Computer software]. Retrieved from https://cran.r-project.org. (R packages retrieved from MRAN snapshot 2021-04-01).
[3] Viechtbauer, W. (2010). Conducting meta-analyses in R with the metafor package. Journal of Statistical Software. link, 36, 1-48.