A Guide to Conducting a Meta-Analysis with Non-Independent Effect Sizes

Cheung, Mike W.‐L.

doi:10.31234/osf.io/5p7dj

Cited by 60 publications

(81 citation statements)

References 29 publications

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“…Finally, restricted likelihood three-level meta-regression models were used to investigate the moderating effect of AMSTAR score, year of publication and number of included studies on overall effect estimate on objective cognitive outcomes. Given many of the included reviews provided more than one effect estimate per outcome for analysis, three-level metaregression analyses assessed the extent to which the model explains heterogeneity within ( (2) 2 ) and between studies ( (3) 2 ), expressed as (2) 2 and (3) 2 , respectively (Cheung, 2019) .…”

Section: Discussionmentioning

confidence: 99%

“…Analyses of composite scores of multiple outcome measures might avoid this problem, but may overestimate within-study variance and thus underestimate between-study heterogeneity. Multivariate and multilevel approaches are likely to be more efficient alternatives, as they account for within-and between-study variance and thus allow not only to control for dependency among effect sizes but also to investigate potential sources of variance in each level (for review, see Cheung, 2019).…”

Section: Implications For Researchmentioning

confidence: 99%

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Cognition-oriented treatments for older adults: A systematic overview of systematic reviews

Gavelin¹,

Lampit²,

Hallock³

et al. 2019

Preprint

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Cognition-oriented treatments (COTs) -commonly categorized as cognitive training, cognitive rehabilitation and cognitive stimulation -are promising approaches for the prevention of cognitive and functional decline in older adults. We conducted a systematic overview of meta-analyses investigating the efficacy of COTs on cognitive and non-cognitive outcomes in older adults with or without cognitive impairment. Review quality was assessed by AMSTAR 2. We identified 51 eligible reviews, 46 of which were included in the quantitative synthesis. The confidence ratings were "moderate" for 9 (20%), "low" for 13 (28%) and "critically low" for 24 (52%) of the 46 reviews. While most reviews provided pooled effect estimates for objective cognition, non-cognitive outcomes of potential relevance were more sparsely reported. The mean effect estimate on cognition was small for cognitive training in healthy older adults (Hedge's g 0.32, range 0.13-0.64, 19 reviews), mild cognitive impairment (Hedge's g 0.40, range 0.32-0.60, five reviews), and dementia (Hedge's g 0.38, range 0.09-1.16, seven reviews), and small for cognitive stimulation in dementia (Hedge's g 0.36, range 0.26-0.44, five reviews). Meta-regression revealed that higher AMSTAR score was associated with larger effect estimates for cognitive outcomes. The available evidence supports the efficacy of COTs improving cognitive performance in older adults. The extent to which such effects are of clinical value remains unclear, due to the scarcity of high-quality evidence and heterogeneity in reported findings. An important avenue for future trials is to include relevant non-cognitive outcomes in a more consistent way and, for meta-analyses in the field, there is a need for better adherence to methodological standards. PROSPERO registration number: CRD42018084490.

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Section: Discussionmentioning

confidence: 99%

Section: Implications For Researchmentioning

confidence: 99%

Cognition-oriented treatments for older adults: A systematic overview of systematic reviews

Gavelin¹,

Lampit²,

Hallock³

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…For example, if a study had several treatments (e.g., N addition rates) or the responses were measured several times over the study period (e.g., annually), the observations were non‐independent. However, all these observations were extracted and included into the dataset, to utilize all available data to address relevant questions (Cheung, 2015a, 2019), such as how N addition rate and experimental duration affect the responses. It should be noted that, since multiple observations for the same species in the same study are non‐independent, and to take the non‐independence into account, they were treated using a “shifting the unit of analysis” approach in the present study (see Section 2.4.2 below).…”

Section: Materialsandmethodsmentioning

confidence: 99%

“…We also conducted a three‐level meta‐analysis using the metaSEM package in R, which was proposed to deal with non‐independent effect sizes (Cheung, 2015b, 2019). The results of the conventional meta‐analysis and those of the three‐level meta‐analysis were similar (Table S2).…”

Section: Materialsandmethodsmentioning

confidence: 99%

Global response patterns of plant photosynthesis to nitrogen addition: A meta‐analysis

Liang

Zhang

et al. 2020

Global Change Biology

185

129

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A mechanistic understanding of plant photosynthetic response is needed to reliably predict changes in terrestrial carbon (C) gain under conditions of chronically elevated atmospheric nitrogen (N) deposition. Here, using 2,683 observations from 240 journal articles, we conducted a global meta-analysis to reveal effects of N addition on 14 photosynthesis-related traits and affecting moderators. We found that across 320 terrestrial plant species, leaf N was enhanced comparably on mass basis (N mass , +18.4%) and area basis (N area , +14.3%), with no changes in specific leaf area or leaf mass per area. Total leaf area (TLA) was increased significantly, as indicated by the increases in total leaf biomass (+46.5%), leaf area per plant (+29.7%), and leaf area index (LAI, +24.4%). To a lesser extent than for TLA, N addition significantly enhanced leaf photosynthetic rate per area (A area , +12.6%), stomatal conductance (g s , +7.5%), and transpiration rate (E, +10.5%). The responses of A area were positively related with that of g s , with no changes in instantaneous water-use efficiency and only slight increases in long-term water-use efficiency (+2.5%) inferred from 13 C composition. The responses of traits depended on biological, experimental, and environmental moderators. As experimental duration and N load increased, the responses of LAI and A area diminished while that of E increased significantly. The observed patterns of increases in both TLA and E indicate that N deposition will increase the amount of water used by plants. Taken together, N deposition will enhance gross photosynthetic C gain of the terrestrial plants while increasing their water loss to the atmosphere, but the S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section. How to cite this article: Liang X, Zhang T, Lu X, et al. Global response patterns of plant photosynthesis to nitrogen addition: A meta-analysis. Glob Change Biol. 2020;26:3585-3600. https://doi.

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“…Pooling of outcomes across studies will be conducted using random-effects models. All eligible outcomes per analysis will be used, accounting for dependency structure of effect sizes within studies [26,27]. Sensitivity analyses for the primary outcome will be conducted by comparing results from multilevel and robust variance estimation models.…”

Section: Data Synthesismentioning

confidence: 99%

Computerized Cognitive Training in People with Depression: A Protocol for a Systematic Review and Meta-Analysis

Lampit

Launder

Minkov

et al. 2020

Preprint

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Background People with depression often present with concurrent cognitive impairment. Computerized cognitive training (CCT) is safe and efficacious strategy to maintain or enhance cognitive performance in a range of clinical populations. However, its efficacy in people with depression and how it varies across populations and design factors is currently unclear. Methods We searched MEDLINE, EMBASE and PsycINFO from inception to 29 June 2020 for randomised controlled trials examining the efficacy of CCT vs any control condition on cognitive, mood, psychiatric symptoms, psychosocial functioning and daily function in adults with depression. Eligible samples include studies specifically targeting people with major depressive disorder as well as those with other diagnoses where at least 50% of the sample meets clinical criteria for depression, with the exception of major psychiatric disorders or dementia. The primary outcome is change in overall cognitive performance. Multivariate analyses will be used to examine effect sizes on each outcome category as well as possible effect modifiers and correlations between categories. Risk of bias will be assessed using the Cochrane risk of bias tool version 2. Discussion To the best of our knowledge, this will be the first systematic review and meta-analysis of narrowly-defined CCT across clinical populations with depression. We aim to investigate not only whether CCT is efficacious for cognition, but also how such effects vary across design factors, what other clinically relevant outcomes might respond to CCT and the extent to which they differ across populations. Systematic review registration: Submitted and pending evaluation with PROSPERO.

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A Guide to Conducting a Meta-Analysis with Non-Independent Effect Sizes

Cited by 60 publications

References 29 publications

Cognition-oriented treatments for older adults: A systematic overview of systematic reviews

Cognition-oriented treatments for older adults: A systematic overview of systematic reviews

Global response patterns of plant photosynthesis to nitrogen addition: A meta‐analysis

Computerized Cognitive Training in People with Depression: A Protocol for a Systematic Review and Meta-Analysis

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