Multilevel Meta-analysis Research Articles

Dung beetles increase plant growth: a meta-analysis.

The ecosystem services provided by dung beetles are well known and valued. Dung beetles bury dung for feeding and breeding, and it is generally thought that the process of burying dung increases nutrient uptake by plant roots, which promotes plant growth. Many studies have tested the effects of dung beetles on plant growth, but there has been no quantitative synthesis of these studies. Here we use a multi-level meta-analysis to estimate the average effect of dung beetles on plant growth and investigate factors that moderate this effect. We identified 28 publications that investigated dung beetle effects on plant growth. Of these, 24 contained the minimum quantitative data necessary to include in a meta-analysis. Overall, we found that dung beetles increased plant growth by 17%; the 95% CI for possible values for the true increase in plant growth that were most compatible with our data, given our statistical model, ranged from 1% to 35%. We found evidence that the dung beetle-plant growth relationship is influenced by the plant measurement type and the number of beetles accessing the dung. However, beetles did not increase plant growth in all quantitative trials, as individual effect sizes ranged from -72% to 806%, suggesting important context-dependence in the provision of ecosystem services.

Linking childhood maltreatment to cyberbullying perpetration and victimization: A systematic review and multilevel meta-analysis

Both theoretical and empirical evidence has suggested that childhood maltreatment is positively associated with cyberbullying involvement (perpetration and victimization). However, empirical evidence on the strength of such positive associations is not yet clear. To clarify the strength of the associations, the current meta-analysis examined the extent to which childhood maltreatment is correlated with cyberbullying (perpetration and victimization), and whether these associations varied by sample, publication, and research design characteristics. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a total of 57 studies (N = 98,351 participants) involving 281 effect sizes were included through a systematic literature search of five databases and auxiliary searches. An advanced multilevel meta-analysis approach was employed in R to synthesize the effect sizes. No significant publication bias was found. Results showed that childhood maltreatment was significantly and positively related to both cyberbullying perpetration (mean r = 0.349, p < 0.001) and victimization (mean r = 0.237, p < 0.001). Further, moderator analyses revealed that the association between childhood maltreatment and cyberbullying perpetration was stronger for young adults than for adolescents. Finally, the associations between childhood maltreatment and both cyberbullying perpetration and victimization were stronger for emotional abuse than neglect. The findings suggest that childhood maltreatment is a risk factor for developing both cyberbullying perpetration and victimization. Childhood maltreatment warrants attention in the design of comprehensive prevention and intervention programs for cyberbullying (perpetration and victimization).

A Multilevel Meta-Analysis of Synchronous Paired Oral Reading Techniques in Elementary Classrooms

A Multilevel Meta-Analysis of Synchronous Paired Oral Reading Techniques in Elementary Classrooms

Parental differential treatment of siblings linked with internalizing and externalizing behavior: A meta-analysis.

This meta-analysis linked relative and absolute parental differential treatment (PDT) with internalizing and externalizing behavior of children and adolescents. Multilevel meta-analysis data represented 26,451 participants based on 2890 effect sizes coming from 88 sources, nested within 43 samples. Participants were between 3.18 and 18.99 years of age (Mage = 12.64, SD = 3.89; 51.31% female; 82.23% White; 54.68% from the United States). Less-favored treatment (relative PDT) was linked to more internalizing and externalizing behavior. Additionally, greater differences in parenting between siblings (absolute PDT) were linked to more internalizing and externalizing behavior. Some links were moderated by other factors. For example, some effects were stronger when PDT was reported by children, and others, when siblings were closer in age.

The reciprocity between various motivation constructs and academic achievement: a systematic review and multilevel meta-analysis of longitudinal studies

The current multilevel meta-analyses and systematic review encompass 47 longitudinal studies of motivation and academic achievement in primary and secondary education. Our inclusion criteria extended beyond studies centred on self-belief type of motivation constructs, as we also selected studies using other motivation constructs (e.g. achievement goals). The findings offered mixed support for the reciprocity. The pooled effect of achievement on motivation was nearly twice as strong (β = 0.176) as that of motivation on achievement (β = 0.096). The effect of achievement on motivation held across different motivation constructs, albeit exhibiting more robust reciprocity for self-belief constructs (β = 0.227) than for other constructs (β = 0.091). The effect of motivation on achievement was exclusively found for self-belief (β = 0.157) and not for non-self-belief motivation. Overall, the medium-to-high heterogeneity between studies and within studies suggests that pivotal factors in the motivation–achievement dynamics may not have been captured yet.

Online parenting support: Meta-analyses of non-inferiority and additional value to in-person support

Parenting support to enhance parent and child mental health is increasingly offered on websites, apps, and through videocall. This development raises the question of how online parenting support compares to traditional in-person parenting support. Is online support non-inferior to traditional in-person support? Or should online support be used as a supplement to in-person support? In the COST Action EurofamNet (CA18123), we sought to answer these questions by systematically searching for randomized trials comparing online to in-person parenting support (Study 1) and trials comparing in-person parenting support augmented with online support elements to in-person parenting support only (Study 2). We registered our review in PROSPERO (CRD42022354393) and searched PsycINFO, MEDLINE, Web of Science, and Cochrane in May 2022. Our outcomes of interests were children’s mental health, parenting practices, parental mental health, and parents’ satisfaction with the program. For Study 1, multilevel meta-analysis of seven eligible randomized trials (101 effect sizes; N = 957) showed consistent non-inferiority of online support and a trend that parents were more satisfied with online support. For Study 2, narrative synthesis of two eligible trials (N = 279) suggests that adding online support elements to in-person support can improve program satisfaction and short-term benefits, but does not contribute significantly to program benefits above and beyond in-person support. Our findings suggest that, provided appropriate online formats and sufficient guidance from professionals, online parenting support is non-inferior to in-person support. The additive value of online support elements to in-person support seems limited, but may still be meaningful. Future research should identify the circumstances under which parents prefer, and benefit more from, in-person versus online parenting support.

A Comparison of Single-Case Effect Measures Using Check-In Check-Out Data.

There are numerous effect measures researchers can select when conducting a meta-analysis of single-case experimental design research. These effect measures model different characteristics of the data, so it is possible that a researcher's choice of an effect measure could lead to different conclusions about the same intervention. The current study investigated the impact of effect measure selection on conclusions about the effectiveness of check-in check-out (CICO), a commonly used intervention within School-Wide Positive Behavior Interventions and Supports. Using a multilevel meta-analysis of seven different effect measures across 95 cases in 22 studies, findings suggested that all effect measures indicated statistically significant results of CICO in improving student behavior. However, the magnitude of the effects varied when comparing the results to interpretive guidelines, suggesting that the selection of effect measures may impact conclusions regarding the extent to which an intervention is effective. Implications, limitations, and future directions are discussed.

Effect of vegetable consumption on risk of gastric cancer: a systematic review and multi-level meta-analysis of prospective studies.

Vegetables are known to be beneficial to human health, but the association between vegetable consumption and gastric cancer remains uncertain. To synthesise knowledge about the relationship between vegetable group consumption and gastric cancer risk, update present meta-analyses and estimate associations between vegetable consumption and gastric cancer risk based solely on prospective studies, we perform a PRISMA-compliant three-level meta-analysis. Systematic search identified thirteen prospective studies with fifty-two effect sizes that met all inclusion criteria and no exclusion criteria for our meta-analysis. Pooled risk ratios (RRs) showed a positive association between high vegetable consumption and low gastric cancer risk (pooled RR 0·93, 95% confidence interval 0·90-0·97, P = 0·06). In moderator analyses for indicators of gender, region and quantity of vegetable intake, there was no significant difference between subgroups. However, the effect became significant in populations with lower than the minimum risk exposure level (TMREL) of vegetable consumption (P < 0·05). Higher vegetable intake is associated with a decreased risk of gastric cancer. This effect may be limited to specific populations, such as ones with lower vegetable consumption. Evidence from our study has important public health implications for dietary recommendations.

Effect of exercise for depression: systematic review and network meta-analysis of randomised controlled trials

ObjectiveTo identify the optimal dose and modality of exercise for treating major depressive disorder, compared with psychotherapy, antidepressants, and control conditions.DesignSystematic review and network meta-analysis.MethodsScreening, data extraction, coding, and risk...

Nonpharmacological Therapies for Musculoskeletal Injury in Military Personnel: A Systematic Review/Meta-Analysis.

Musculoskeletal (MSK) injury is an inherent risk for military personnel that can potentially impact job performance, productivity, and military readiness. Evidence is needed to show the efficacy of nonpharmacological, self-managed therapies to reduce MSK symptoms at common injury sites that are feasible for use during expeditionary operations and home stations. This systematic review and meta-analysis identified, summarized, and synthesized available evidence from randomized and non-randomized trials on the effectiveness of self-managed, home-use therapies to improve pain, muscle strength, and physical performance in military personnel with MSK injuries, when compared to controls. The electronic databases of MEDLINE ALL Ovid, Embase.com, Cochrane Library, Scopus, Clinicaltrial.gov, and CINAHL Complete via EBSCO were systematically searched for relevant reports published in English. Utilizing the Covidence platform and consistent with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, multiple reviewers, using pre-determined data fields, screened for eligibility, assessed risk of bias (RoB), and performed data extraction. Evaluation of treatment effectiveness was determined using multilevel mixed-effects meta-analysis. The database and register search yielded 1,643 reports that were screened for eligibility. After screening of titles/abstracts and full texts, 21 reports were identified for evidence synthesis. Of these, two reports were excluded and two described the same study, resulting in a final list of 18 studies (19 reports). For quality assessment, the overall RoB for the 18 studies was categorized as 33.3% low risk, 55.6% with some concerns, and 11.1% high risk. Across the five domains of bias, 70% of the reports were classified as low risk. This systematic review found that the differences in interventions, outcome measures, and design between the studies were associated with a substantial degree of heterogeneity (I2 = 60.74%), with a small overall improvement in outcomes of the interventions relative to their specific control (standard mean difference 0.28; 95% CI, 0.12 to 0.45). There were varying degrees of heterogeneity for individual body regions. This was due, in part, to a small number of studies per bodily location and differences in the study designs. For the neck/shoulder, heterogeneity was moderate, with the clearest positive effect being for physical performance outcomes via other medical devices. For the back, there was substantial heterogeneity between studies, with modest evidence that pain was favorably improved by other medical devices and exercise interventions. For the leg, one study showed a clear large effect for other medical devices (shockwave treatment) on pain with substantial heterogeneity. The best evidence for positive effects was for the knee, with mainly negligible heterogeneity and some benefits from bracing, electrotherapy, and exercise. Evidence showed small beneficial effects in pain, strength, and physical performance by individual body regions for some interventions, compared to controls. The best evidence for a positive effect was for the knee. The findings suggest that some benefit may be obtained by including several treatments during deployment in austere environments and prolonged casualty care scenarios of military personnel with MSK injuries. Further research is warranted to better assess the potential benefits of using these treatments during deployments in austere environments as part of an individualized, multimodal approach for MSK injuries.

The effects of study abroad on L2 vocabulary development

Abstract While research on second language (L2) vocabulary development after a study abroad (SA) experience has been largely investigated, findings are still not clear-cut because of the multifaceted nature of vocabulary and the different methodologies used when investigating its growth. For this reason, the aim of the present study was to elucidate the link between SA and lexical development. A multilevel meta-analysis including 25 studies was conducted to examine the extent to which overall, receptive vocabulary (RV) and productive vocabulary (PV) are impacted by a SA experience. A second objective was to determine whether length of stay (LoS) in the target country has an effect on L2 vocabulary development. Results showed that international stays have a significantly large impact on RV and overall vocabulary and a significantly moderate impact on PV. The analysis also showed that LoS alone cannot be used as a predictor of gains in the students’ L2 vocabulary.

A meta-analysis of the effect of visiting zoos and aquariums on visitors' conservation knowledge, beliefs, and behavior.

Zoos and aquariums are well placed to connect visitors with the issues facing biodiversity globally and many deliver interventions that seek to influence visitors' beliefs and behaviors with respect to conservation. However, despite primary studies evaluating the effect of such interventions, the overall effect of engaging with zoos and the factors that influence this effect remain unclear. We conducted a systematic review to investigate the effect of zoo-led interventions on knowledge, beliefs (attitudes, intentions, self-efficacy, and social norms), and behavior among zoo visitors. These outcomes were identified using the Theory of Planned Behavior as a theoretical lens. We identified and described the nature of zoo-led interventions in 56 studies and used the behavior change technique (BCT) taxonomy to identify 6 specific BCTs used in interventions to date. Multilevel meta-analyses revealed a small to medium positive effect of engaging with zoo-led interventions on outcomes (d+ =0.40, 95% confidence interval=0.28-0.51). Specifically, visitors were more knowledgeable about conservation issues, held more favorable attitudes toward conservation, and reported being more likely to act for the benefit of biodiversity. No evidence of publication bias was present. Effect sizes were, however, heterogeneous and subgroup analyses revealed that the nature of the intervention or type of outcome did not explain this variance. Larger effects were, however, found in studies conducted at a single institution relative to research at multiple institutions and studies that used within-participant designs relative to between-participant designs. Taken together, these findings demonstrate how behavior change frameworks can be used to describe zoo-led interventions and supports the assertion that zoos and aquariums can promote changes in beliefs and behaviors that may help protect biodiversity.

Species sensitivities to artificial light at night: A phylogenetically controlled multilevel meta-analysis on melatonin suppression.

The rapid urbanization of our world has led to a surge in artificial lighting at night (ALAN), with profound effects on wildlife. Previous research on wildlife's melatonin, a crucial mechanistic indicator and mediator, has yielded inconclusive evidence due to a lack of comparative analysis. We compiled and analysed an evidence base including 127 experiments with 437 observations across 31 wild vertebrates using phylogenetically controlled multilevel meta-analytic models. The evidence comes mainly from the effects of white light on melatonin suppression in birds and mammals. We show a 36% average decrease in melatonin secretion in response to ALAN across a diverse range of species. This effect was observed for central and peripheral melatonin, diurnal and nocturnal species, and captive and free-living populations. We also reveal intensity-, wavelength-, and timing-dependent patterns of ALAN effects. Exposure to ALAN led to a 23% rise in inter-individual variability in melatonin suppression, with important implications for natural selection in wild vertebrates, as some individuals may display higher tolerance to ALAN. The cross-species evidence has strong implications for conservation of wild populations that are subject to natural selection of ALAN. We recommend measures to mitigate harmful impacts of ALAN, such as using 'smart' lighting systems to tune the spectra to less harmful compositions.

A Multilevel Meta-analysis of Language Mindsets and Language Learning Outcomes in Second Language Acquisition Research

A Multilevel Meta-analysis of Language Mindsets and Language Learning Outcomes in Second Language Acquisition Research

Physical Activity and Mental Health in Children and Adolescents With Neurodevelopmental Disorders

Children and adolescents with neurodevelopmental disorders experience mental health issues and are encouraged to be brought together in real-life treatment. However, physical activity, which is a promising method for boosting mental health, has only been examined in children and adolescents with certain types of neurodevelopmental disorders. To examine the association of physical activity interventions with mental health (ie, cognitive function, psychological well-being, internalizing, and externalizing problems) in children and adolescents with neurodevelopmental disorders and to identify possible moderators. Studies were searched from inception to May 2023 through Web of Science, PsycINFO, SPORTDiscus, MEDLINE, CINAHL, and ERIC. Randomized clinical trials or nonrandomized designs applying physical activity interventions and reporting at least 1 mental health outcome in children and adolescents aged 5 to 17 years with neurodevelopmental disorders were included. Two independent reviewers selected and assessed the studies. Random multilevel meta-analysis using Hedges g was performed. Data extraction and risk-of-bias assessment were conducted by multiple reviewers. Heterogeneity, publication bias, sensitivity analysis, and moderator analysis were examined to substantiate the results. The main outcomes were mental health related to cognitive function, psychological well-being, internalizing, or externalizing problems measured by neurocognitive tasks or subjective questionnaires. A total of 76 studies involving 3007 participants were included in systematic review, 59 of which were used for meta-analysis. The findings indicated that physical activity interventions were associated with significant benefits for overall mental health (g, 0.67; 95% CI, 0.50-0.85), cognitive function (g, 0.74; 95% CI, 0.53-0.95), psychological well-being (g, 0.56; 95% CI, 0.16-0.96), internalizing (g, 0.72; 95% CI, 0.34-1.10), and externalizing problems (g, 0.58; 95% CI, 0.28-0.89). Moderators were also identified: frequency, total sessions, and total duration for overall mental health; total sessions, and total duration for cognitive function; session duration and frequency for psychological well-being; physical activity type for internalizing problems; and session duration for externalizing problems. Moderator analyses showed that type of neurodevelopmental disorder did not modify the associations between physical activity and overall mental health or its subgroups. The findings in this study suggest that children and adolescents with different types of neurodevelopmental disorders may be grouped together when performing physical activity interventions, which were confirmed to be beneficial to overall mental health and its subgroups in this new diagnostic population, but that physical activity interventions should be tailored when targeting different mental health domains.

Debugging in Computational Thinking: A Meta-analysis on the Effects of Interventions on Debugging Skills

Computational thinking (CT), an essential 21st century skill, incorporates key computer science concepts such as abstraction, algorithms, and debugging. Debugging is particularly underrepresented in the CT training literature. This multi-level meta-analysis focused on debugging as a core CT skill, and investigated the effects of various debugging interventions. Moderator analyses revealed which interventions were effective, in which situations, and for what kind of learner. A significant overall mean effect of debugging interventions ([Formula: see text] = 0.64, CI = (0.32, 0.96), p &lt; .001), was found based on 62 effect sizes from 18 source articles. Significant between-studies variation indicated that true effects could range from −0.54 to 1.82. In addition, sensitivity analyses and checks on confounding provided further understandings of intervention features and their impacts. Interventions using enhanced debuggers and systematic instruction were particularly effective in fostering debugging skills. Debugging intervention effects varied by participant population and potentially by publication type. Moreover, debugging interventions had impact regardless of how debugging skills were measured, programming medium used, control-group type, and whether the study was randomized. Future studies should investigate the best practices for improving debugging abilities for whom and under what circumstances.

Meta-analysis of the prevalence of norovirus and hepatitis a virus in berries

Norovirus (NoV) and hepatitis A virus (HAV) stand as the predominant agents associated with viral foodborne infections. Outbreaks have been documented to be caused by various types of food items, including fresh and/or frozen berries. Comprehensive data concerning crucial viral pathogens in berries remain limited and are not currently available in aggregate form. Consequently, the present study aimed to compile the existing information regarding the prevalence of NoV and HAV in this matrix. Records of foodborne viruses were systematically extracted from database repositories up to December 2022, adhering to PRISMA standards and were subjected to a multilevel random effect meta-analysis model to determine the mean occurrence rate of NoV and HAV. A high heterogeneity across studies was observed (I2 = 82 %), reflecting variations in the prevalence of sampling locations, years, berry types, and sample conditions, among other potential contributing factors. The prevalence of NoV and HAV in berries was calculated at 2.12 % (95 % CI 1.74–2.59 %), and no statistically differences were observed among the viral types or genogroup categories. However, it is important to clarify that this estimate should be taken with caution given the high heterogeneity. There was no discernible correlation between viral prevalence and any particular berry type. However, there was a temporal correlation observed with the year of sampling, revealing a significantly decreasing trend throughout the study period. A significant influence of the sample condition (fresh or frozen) was observed in relation to the prevalence of NoV GII and HAV. Overall higher viral prevalences were identified in berries originating from African countries as compared to those sourced from other continents. It was also noted that the prevalence of NoV GI was significantly higher in samples collected directly from farms compared to those obtained from retailers. The outcomes of this comprehensive meta-analysis propose that while viral contamination of berries is diminishing in more recent times, the prevalence remains substantial in certain African countries, having a significant risk for foodborne infections. It is imperative to implement intervention strategies in these regions to enhance product safety.

Digital Health Interventions for Quality Improvements in Chronic Kidney Disease Primary Care: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Chronic kidney disease (CKD) is a significant public health issue globally. The importance of its timely identification and early intervention is paramount. However, a systematic approach for early CKD management in the primary care setting is currently lacking, receiving less attention compared to upstream risk factors such as diabetes and hypertension. This oversight may lead to a failure in meeting quality-of-care indicators. Digital health interventions (DHIs), which leverage digital tools to enhance healthcare delivery, have shown effectiveness in managing chronic diseases and improving the quality, safety, and efficiency of primary care. Our research aimed to evaluate the effectiveness of DHIs in the care process, focusing on their reach, uptake, and feasibility. In this systematic review and meta-analysis, we searched PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and ClinicalTrials.gov for randomized controlled trials (RCTs) assessing DHIs' effectiveness in CKD patient care among adults in primary care settings. The search, conducted on 30 June 2023, included studies published in English from 1 January 2009. Screening was conducted using Covidence, adhering to Cochrane's guidelines for data extraction. We primarily evaluated changes in care processes (testing, documentation, medication use, etc.) and the use of renin-angiotensin-aldosterone system inhibitors (RAASi), referrals, among others. Multilevel meta-analysis was employed to address within-study clustering, and meta-regression analyzed the impact of study characteristics on heterogeneity in effect sizes. Clinical endpoints were recorded where available. Bias risk was assessed using the Cochrane Risk of Bias 2 tool. Data on reach, uptake, and feasibility were narratively summarized. The study is registered with PROSPERO (CRD42023449098). From 679 records, 12 RCTs were included in the narrative synthesis, and 6 studies (encompassing 7 trials) in the meta-analysis. The trials indicated a -0.85% change (95%CI, -5.82% to 4.11%) in the proportion of patients receiving desired care. This result showed considerable heterogeneity (I2 = 91.9%). One study characteristic (co-intervention, education) correlated with larger effects. Although including co-intervention in multivariable meta-regression was significant, it did not diminish heterogeneity. The reported reach varied and was not high, while the uptake was relatively high. Most studies did not explicitly address feasibility, though some statements implied its evaluation. The current literature on the impact of DHIs in community-based CKD care is limited. The studies suggest a non-significant effect of DHIs on enhancing CKD management in community settings, marked by significant heterogeneity. Future research should focus on rigorous, methodologically sound implementations to better assess the effectiveness of DHIs in the primary care management of CKD.

The Effect of Sodium-Glucose Cotransporter Inhibitors on Renal Function as Adjunctive to Insulin in Adults with Type1 Diabetes: An Updated Multilevel Meta-analysis of Randomized Controlled Trials.

This systematic review aimed to summarize the existing evidence from published randomized controlled trials (RCTs) on the impact of sodium-glucose cotransporter (SGLT) inhibitors on albuminuria levels and renal function in patients with type1 diabetes mellitus (T1D). The literature search was performed through Medline (via PubMed), Cochrane Library, and Scopus until November11, 2023. Double-independent study selection, data extraction, and quality assessment were performed. Evidence was pooled with three-level mixed-effects meta-analysis. In total, 5221 participants with T1D among 11 RCTs were analyzed. All RCTs had low risk of bias according to the Cochrane Collaboration tool (RoB2). SGLT inhibitors were associated with a significantly greater reduction in urine albumin-to-creatinine ratio (UACR) compared to controls (MD = - 23.13%; 95%CI = [- 33.69, - 12.57]; P < 0.001; level of evidence high). On the basis of subgroup analysis, this effect was consistent across all available SGLT inhibitors, irrespective of the dosage. Finally, a neutral class effect was observed on the estimated glomerular filtration rate (eGFR, MD = - 1.03mL/min/1.73m2; 95%CI = [- 2.26, 0.19]; P = 0.1; level of evidence moderate). Only empagliflozin was associated with a significant reduction in eGFR compared to placebo (MD = - 2.23mL/min/1.73m2; 95%CI = [- 3.62, - 0.84]; P = 0.002). Our findings suggest that adjunctive therapy with SGLT inhibitors results in a significant reduction in albuminuria, while their use is associated with a neutral effect on creatinine clearance, as a measure of renal function. Future renal outcome trials are needed to assess SGLT inhibitors' role in the pharmacological armamentarium against diabetic nephropathy in T1D.

Acute and chronic effects of stretching on balance: a systematic review with multilevel meta-analysis.

Balance is a multifactorial construct with high relevance in, e.g., everyday life activities. Apart from sensorimotor control, muscle strength and size are positively linked with balance performance. While commonly trained for via resistance training, stretch training has emerged as a potential substitution in specific conditions. However, no review has investigated potential effects of stretching on balance, yet. PubMed, Web of Science and Scopus were searched with inception to February, 2024. Studies were included if they examined acute and/or chronic effects of any stretching type against passive and/or active controls on balance parameters - without any population-related restrictions concerning sex/gender, age, health status, activity level. Methodological quality was assessed using PEDro scale. Meta-analyses were performed if two or more studies reported on the same outcome. Certainty of evidence was determined based on GRADE criteria. Eighteen acute and eleven chronic effect studies were included. Stretching studies exhibited significant improvements for sway parameters with eyes open against passive controls of moderate magnitude for chronic (ES: 0.63, p = 0.047) and of small magnitude for acute studies (ES: 0.21, p = 0.032). Most other subgroups against passive controls as well as actively-controlled comparisons resulted in trivial and/or non-significant effects. Even though some pooled effects slightly reached the level of significance, the overall results are biased by (very) low certainty of evidence (GRADE criteria downgrading for risk of bias, imprecision, publication bias). Moderators suggested by literature (strength, muscle size, flexibility, proprioception) were rarely assessed, which prevents conclusive final statements and calls for further, high quality evidence to clarify potential mechanisms-if any exist.