Median Effect Size Research Articles

Gene variants and the response to childhood obesity interventions: A systematic review and meta-analysis

Multiple lifestyle-based childhood obesity interventions have been conducted to address childhood obesity, but individual's response to the universal intervention approach varied greatly. Whether gene variants related to children and adolescents' varied responses to obesity interventions remained unclear. To determine the associations of gene variants with the changes in obesity- and metabolism-related indicators after obesity interventions in children and adolescents. Ten databases and registers (including grey literature) were searched. The lifestyle-based obesity interventions in children and adolescents (≤18 years) that reported the changes in obesity- (body mass index (BMI), BMI Z-score, waist circumference (WC), waist-to-hip ratio (WHR), etc) and metabolism-related (glucose, cholesterol, etc) indicators by genotype after interventions were included. Our primary outcome was the mean difference of the changes in BMI Z-score by genotype after interventions, and secondary outcomes were changes in the remaining obesity- and metabolism-related indicators after interventions. We used the random-effects model to synthesize the results. This review included 50 studies (15,354 children and adolescents with overweight/obesity) covering 102 genes and 174 single nucleotide polymorphisms (SNPs). Approximately three-quarters of SNPs showed no evidence of association with the changes in obesity- or metabolic-related indicators after interventions. One quarter of SNPs were minorly associated with the changes in the BMI Z-score (median effect size: 0.001) with little clinical significance. Only 6 (12%) studies focused on the accumulated effect of multiple gene variants. Gene variants that have been explored appear to play a minor role in lifestyle-based obesity interventions in children and adolescents. More high-quality studies based on the design of randomized controlled trials are needed to examine the accumulated effect of multiple gene variants in childhood obesity interventions. This systematic review and meta-analysis was registered at PROSPERO as CRD42022312177.

Systematic examination of methodological inconsistency in operationalizing cognitive reserve and its impact on identifying predictors of late-life cognition

BackgroundCognitive reserve (CR) is the ability to maintain cognitive performance despite brain pathology. CR is built through lifecourse experiences (e.g., education) and is a key construct in promoting healthy aging. However, the operationalization of CR and its estimated association with late-life cognition varies. The purpose of this study was to systematically examine the operationalization of CR and the relationship between its operationalization and late-life cognition.MethodsWe performed a comprehensive review of experiences (proxies) used to operationalize CR. The review informed quantitative analyses using data from 1366 participants of the Memory and Aging Project to examine 1) relationships between proxies and 2) the relationship between operationalization and late-life cognition. We also conducted a factor analysis with all identified CR experiences to create a composite lifecourse CR score. Generalized linear mixed models examined the relationship between operationalizations and global cognition, with secondary outcomes of five domains of cognition to examine consistency.ResultsBased on a review of 753 articles, we found the majority (92.3%) of the 28 commonly used proxies have weak to no correlation between one another. There was substantial variability in the association between operationalizations and late-life global cognition (median effect size: 0.99, IQR: 0.34 to 1.39). There was not strong consistency in the association between CR operationalizations and the five cognitive domains (mean consistency: 56.1%). The average estimate for the 28 operationalizations was 0.91 (SE = 0.48), compared to 2.48 (SE = 0.40) for the lifecourse score and it was associated with all five domains of cognition.ConclusionsInconsistent methodology is theorized as a major limitation of CR research and barrier to identification of impactful experiences for healthy cognitive aging. Based on the weak associations, it is not surprising that the relationship between CR and late-life cognition is dependent on the experience used to operationalize CR. Scores using multiple experiences across the lifecourse may help overcome such limitations. Adherence to a lifecourse approach and collaborative movement towards a consensus operationalization of CR are imperative shifts in the study of CR that can better inform research on risk factors related to cognitive decline and ultimately aid in the promotion of healthy aging.

Appetitive and Aversive Motivation in Dysregulated Behaviors: A Meta-Analysis.

Appetitive and aversive motivation are prominent in theories of dysregulated behaviors. The authors conducted a meta-analysis of the association between individual differences in appetitive and aversive motivation and several dysregulated behaviors (i.e., alcohol use, marijuana use, tobacco use, binge eating, aggression, gambling, and nonsuicidal self-injury). Alcohol use (r = .17, k = 141), marijuana use (r = .13, k = 23), aggression (r = .22, k = 52), and gambling (r = .08, k = 55) were all significantly positively related to appetitive motivation. Binge eating (r = .28, k = 34) and self-injury (r = .17, k = 10) were significantly positively related to aversive motivation. Effect sizes were similar to the median effect size in personality research. Together, these results provide some evidence that some dysregulated behaviors are more correlated with approach motivation, whereas others are more correlated with aversive motivation, which may indicate distinct etiological pathways.

The Effect of Exercise on Pain in People with Cancer: A Systematic Review with Meta-analysis.

Cancer-related pain is common and undertreated. Exercise is known to have a pain-relieving effect in non-cancer pain. This systematic review aimed to evaluate (1) the effect of exercise on cancer-related pain in all cancers, and (2) whether the effect of exercise differed according to exercise mode, degree of supervision, intervention duration and timing (during or after cancer treatment), pain types, measurement tool and cancer type. Electronic searches were undertaken in six databases to identify exercise studies evaluating pain in people with cancer, published prior to 11 January 2023. All stages of screening and data extraction were conducted independently by two authors. The Cochrane risk of bias tool for randomised trials (RoB 2) was used and overall strength of evidence was assessed using the GRADE approach. Meta-analyses were performed overall and by study design, exercise intervention and pain characteristics. In total, 71 studies reported in 74 papers were eligible for inclusion. The overall meta-analysis included 5877 participants and showed reductions in pain favouring exercise (standardised mean difference - 0.45; 95% confidence interval - 0.62, - 0.28). For most (> 82%) of the subgroup analyses, the direction of effect favoured exercise compared with usual care, with effect sizes ranging from small to large (median effect size - 0.35; range - 0.03 to - 1.17). The overall strength of evidence for the effect of exercise on cancer-related pain was very low. The findings provide support that exercise participation does not worsen cancer-related pain and that it may be beneficial. Better pain categorisation and inclusion of more diverse cancer populations in future research would improve understanding of the extent of benefit and to whom. CRD42021266826.

Efficacy of computerized cognitive training and mindfulness for improving cognition and mood in older adults: better together than separately

Background The risk of cognitive decline in older adults makes it necessary to design training programs for the improvement of cognition. Aims To determine the efficacy of applying a combined program of computerized cognitive training (CCT) and mindfulness for improving cognition and mood and quality of life in people aged 60 years and older, compared with using both interventions separately. Methods Adults, older than 95 years were assigned to groups that subsequently received one of the three interventions (CCT, mindfulness, and combined). Cognitive, emotional, and quality of life assessment instruments were administered pre- and post-intervention. The standardized individual change was determined, and one-factor ANOVAs and ANCOVAs were conducted to test between-group differences. Results After controlling for confounding factors, greater significant improvements were obtained in the combined group compared with the CCT and mindfulness groups in selective attention (median effect size) and abstract reasoning (large effect size). No significant differences were found in the rest of cognitive variables, mood or quality of life. Conclusion The findings indicate that, with the same investment of time, combining CCT and mindfulness effectively improves selective attention and abstract reasoning, in older adults. This combination of strategies might have implications for the improvement of cognitive impairment in older adults.

Using the Delphi process to determine the minimum clinically important effect size for the Balanced-2 randomised controlled trial.

The sample size calculation is an important step in designing randomised controlled trials. For a trial comparing a control and an intervention group, where the outcome is binary, the sample size calculation requires choosing values for the anticipated event rates in both the control and intervention groups (the effect size), and the error rates. The Difference ELicitation in TriAls guidance recommends that the effect size should be both realistic, and clinically important to stakeholder groups. Overestimating the effect size leads to sample sizes that are too small to reliably detect the true population effect size, which in turn results in low achieved power. In this study, we use the Delphi approach to gain consensus on what the minimum clinically important effect size is for Balanced-2, a randomised controlled trial comparing processed electroencephalogram-guided 'light' to 'deep' general anaesthesia on the incidence of postoperative delirium in older adults undergoing major surgery. Delphi rounds were conducted using electronic surveys. Surveys were administered to two stakeholder groups: specialist anaesthetists from a general adult department in Auckland City Hospital, New Zealand (Group 1), and specialist anaesthetists with expertise in clinical research, identified from the Australian and New Zealand College of Anaesthetist's Clinical Trials Network (Group 2). A total of 187 anaesthetists were invited to participate (81 from Group 1 and 106 from Group 2). Results from each Delphi round were summarised and presented in subsequent rounds until consensus was reached (>70% agreement). The overall response rate for the first Delphi survey was 47% (88/187). The median minimum clinically important effect size was 5.0% (interquartile range: 5.0-10.0) for both stakeholder groups. The overall response rate for the second Delphi survey was 51% (95/187). Consensus was reached after the second round, as 74% of respondents in Group 1 and 82% of respondents in Group 2 agreed with the median effect size. The combined minimum clinically important effect size across both groups was 5.0% (interquartile range: 3.0-6.5). This study demonstrates that surveying stakeholder groups using a Delphi process is a simple way of defining a minimum clinically important effect size, which aids the sample size calculation and determines whether a randomised study is feasible.

Effectiveness of interventions to prevent perinatal depression: An umbrella review of systematic reviews and meta-analysis

BackgroundTo date, dozens of systematic reviews (SRs) and meta-analyses (MAs) summarize the effectiveness of preventive interventions for perinatal depression. However, the results are inconclusive, making an urgent need to step up to higher levels of evidence synthesis. AimsTo summarize and compare the evidence from the SR&MA examining the effectiveness of all types of interventions for preventing perinatal depression. MethodPubMed, PsycINFO, Cochrane Database of Systematic Reviews and OpenGrey were searched from inception to December 2022. We selected SR&MA of randomized controlled trials (RCTs) that compared all types of preventive interventions for perinatal depression with control groups whose outcome was the reduction of depressive symptoms and/or incidence of new cases of perinatal depression (PROSPERO: CRD42020173125). ResultsA total of 19 SRs and MAs evaluated 152 unique RCTs that included 83,408 women from 26 countries and five continents. The median effect size for any intervention was SMD = 0.29 (95% CI: 0.20 to 0.38). Exercise/physical activity-based, psychological, and any type of intervention showed median effect sizes of 0.43, 0.28 and 0.36, respectively. The degree of overlap among RCTs was slight. According to AMSTAR-2, 79% of them were rated as low or critically low-quality. The strength of evidence, according to GRADE, was poorly reported and, in most cases, was low. ConclusionsExercise/physical activity-based and psychological interventions have a small-to-medium effect on reducing perinatal depressive symptoms. There is insufficient evidence to conclude that dietary supplements and pharmacological interventions are effective in preventing perinatal depression. There is a need for high-quality SR&MA of RCTs, mainly focusing on universal preventive interventions.

Effectiveness of physical activity interventions for improving depression, anxiety and distress: an overview of systematic reviews

ObjectiveTo synthesise the evidence on the effects of physical activity on symptoms of depression, anxiety and psychological distress in adult populations.DesignUmbrella review.Data sourcesTwelve electronic databases were searched for eligible studies...

A Meta-Research of Randomized Controlled Trials in the Field of Mental Health: Comparing Pharmacological to Non-Pharmacological Interventions from 1955 to 2020.

This study aimed to provide a general overview of mental health randomized controlled trials (RCTs) and summarize the temporal trends in terms of the number of studies, median sample sizes, and median effect sizes using data collected from the Cochrane Database of Systematic Reviews (CDSR). Using data collected from the CDSR, the temporal trends are compared in terms of the number of studies, median sample sizes, and median effect sizes between two broad categories of interventions: pharmacological RCT (ph-RCT) and non-pharmacological RCT (nph-RCT), and in conjunction with major mental disorder categories. Chronologically, the number of mental health RCTs reported in publications has increased exponentially from 1955 to 2020. While ph-RCT comprised a majority of mental health RCTs in the earlier years, the proportion of nph-RCTs increased more quickly over time and markedly exceeded ph-RCT after 2010. The median sample size for all 6,652 mental health RCTs was 61, with 61 for ph-RCT and 60 for nph-RCT. Over time, the median fluctuated but an increasing trend was observed over the past 60+ years. The median of the effect size, measured by Pearson's r, for overall RCTs was 0.18, and nph-RCT (0.19) had a larger median effect size compared to ph-RCT (0.16). Over the years, the nph-RCT had a larger median effect size than the ph-RCT. Differences in the median effect sizes among the categories of mental disorders were also noted. Schizophrenia had the most RCTs, with a median Pearson's r value of 0.17. Mood disorder had the second largest number of RCTs and a median Pearson's r value of 0.15. Neurotic/stress-related mental disorder had the third largest number of RCTs with the highest median Pearson's r being 0.23. This study provides meaningful information and filled the knowledge gap in mental health RCTs.

How representative are student convenience samples? A study of literacy and numeracy skills in 32 countries.

Psychological research, including research into adult reading, is frequently based on convenience samples of undergraduate students. This practice raises concerns about the external validity of many accepted findings. The present study seeks to determine how strong this student sampling bias is in literacy and numeracy research. We use the nationally representative cross-national data from the Programme for the International Assessment of Adult Competencies to quantify skill differences between (i) students and the general population aged 16-65, and (ii) students and age-matched non-students aged 16-25. The median effect size for the comparison (i) of literacy scores across 32 countries was d = .56, and for comparison (ii) d = .55, which exceeds the average effect size in psychological experiments (d = .40). Numeracy comparisons (i) and (ii) showed similarly strong differences. The observed differences indicate that undergraduate students are not representative of the general population nor age-matched non-students.

How Big Are Effect Sizes in International Education Studies?

A growing literature measures the impact of education interventions in low- and middle-income countries on both access and learning outcomes. But how should one contextualize the size of impacts? This article provides the distribution of standardized effect sizes on learning and access from 234 studies in low- and middle-income countries. We identify a median effect size of 0.10 standard deviations on learning and 0.07 standard deviations on access among randomized controlled trials. Effect sizes are similar for quasi-experimental studies. Effects are larger and demonstrate higher variance for small-scale studies than for large-scale studies. The distribution of existing effects can help researchers and policymakers to situate new findings within current knowledge and design new studies with sufficient statistical power to identify effects.

Investigating the replicability of preclinical cancer biology.

Replicability is an important feature of scientific research, but aspects of contemporary research culture, such as an emphasis on novelty, can make replicability seem less important than it should be. The Reproducibility Project: Cancer Biology was set up to provide evidence about the replicability of preclinical research in cancer biology by repeating selected experiments from high-impact papers. A total of 50 experiments from 23 papers were repeated, generating data about the replicability of a total of 158 effects. Most of the original effects were positive effects (136), with the rest being null effects (22). A majority of the original effect sizes were reported as numerical values (117), with the rest being reported as representative images (41). We employed seven methods to assess replicability, and some of these methods were not suitable for all the effects in our sample. One method compared effect sizes: for positive effects, the median effect size in the replications was 85% smaller than the median effect size in the original experiments, and 92% of replication effect sizes were smaller than the original. The other methods were binary - the replication was either a success or a failure - and five of these methods could be used to assess both positive and null effects when effect sizes were reported as numerical values. For positive effects, 40% of replications (39/97) succeeded according to three or more of these five methods, and for null effects 80% of replications (12/15) were successful on this basis; combining positive and null effects, the success rate was 46% (51/112). A successful replication does not definitively confirm an original finding or its theoretical interpretation. Equally, a failure to replicate does not disconfirm a finding, but it does suggest that additional investigation is needed to establish its reliability.

Benchmarking the effectiveness of interventions to promote physical activity: A metasynthesis.

The effectiveness of physical activity interventions is typically evaluated using null hypothesis significance testing or conventional interpretations of effect size (i.e., "small," "medium," or "large"). As these criteria have recently attracted criticism, we conducted a quantitative integration of meta-analyses (a metasynthesis) in order to provide precise, numerical estimates of intervention effectiveness. The research aimed to specify the percentile distribution of effect sizes in meta-analyses of physical activity trials, and their corresponding values for different types of activity (i.e., steps per day, minutes of moderate/vigorous physical activity [MVPA], meeting World Health Organization (WHO) physical activity guidelines). Computerized searches identified 104 meta-analyses incorporating findings from 2,762 trials that met the inclusion criteria for the metasynthesis. The median effect size across all meta-analyses was d+ = .21, equivalent to an increase of 1,320 steps per day, 15.6 additional minutes of daily MVPA, and a 4.3% increase in the proportion of participants meeting WHO guidelines. Separate percentile distributions were computed for different samples (e.g., children, older adults, cancer survivors), measures of physical activity (i.e., objective vs. self-report), settings (e.g., schools, workplace), and follow-up periods (3+, 6+, and 12+ months). Conventional interpretations of effect size gravely misrepresent the effectiveness of interventions to promote physical activity. The percentile values for effect sizes, steps per days, minutes of MVPA, and percentage meeting guidelines reported here can be used to benchmark the effectiveness of future trials and should enable more informed judgments about trade-offs between effectiveness and considerations such as reach, burden, and cost. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Assess the Application of the E-Value in the Unmeasured Confounder Evaluation of Observational Pharmaceutical Studies

Public health is very important in big cities, and data analysis on public health studies is always a demanding issue that determines the study effectiveness. E-value was proposed as a standard sensitivity analysis tool to assess unmeasured confounders in observational studies, but its value is doubted. To evaluate the usefulness of E-value, in this paper, we collected 368 observational studies on drug effectiveness evaluation published from 1998 to September 2019 (out of 3426 searched studies) and evaluated the features of E-value. We selected the effects of primary outcomes or the largest effects in terms of hazard ratio, risk ratio, or odds ratio. Effects were transformed into estimated effect sizes following a standard E-value computation. In all 368 studies, the disease with the highest percentage was infections and infestations, at 21.7% (80/368). Our results showed that the median relative effect size was 1.89 (Q1-Q3: 1.41–2.95), and the corresponding median E-value was 3.19 with 95% confidence interval lower bound 1.77. Smaller studies yielded larger E-values for the effect size estimate and the relationship was considerably attenuated when considering the E-value for the lower bound of 95% confidence interval on the effect size. Notably, E-values have a monotonic, almost linear relationship with effect estimates. We found that E-value may cause misimpressions on the unmeasured confounder, and the same E-value does not reflect the varying nature of the unmeasured confounders in different studies, and there lacks a guidance on how E-value can be deemed as small or large, all of which limits the capability of E-value as a standard sensitivity analysis tool in real applications.

Virtual reality cognitive-behavioural therapy versus cognitive-behavioural therapy for paranoid delusions: a study protocol for a single-blind multi-Centre randomised controlled superiority trial

BackgroundSeventy per cent of patients with psychotic disorders has paranoid delusions. Paranoid delusions are associated with significant distress, hospital admission and social isolation. Cognitive-behavioural therapy for psychosis (CBTp) is the primary psychological treatment, but the median effect size is only small to medium. Virtual reality (VR) has a great potential to improve the effectiveness of CBTp. In a previous study, we found that VR based CBT (VRcbt) for paranoid delusions is superior to waiting list. As a next step, a direct comparison with CBTp is needed. The present study aims to investigate whether VRcbt is more effective and cost-effective than regular CBTp in treating paranoid delusions and improving daily life social functioning of patients with psychotic disorders.MethodsA total of 106 patients with DSM-5 diagnosis of psychotic disorder and at least moderate level of paranoid ideations will be recruited for this multicentre randomized controlled trial (RCT). Patients will be randomized to either VRcbt or standard CBTp for paranoid delusions. VRcbt consists of maximum 16 sessions in virtual social situations that trigger paranoid ideations and distress, delivered in an 8–12 week time frame. Standard CBTp also consists of maximum 16 sessions including exposure and behavioural experiments, delivered in an 8–12 week time frame.The two groups will be compared at baseline, post-treatment and six months follow-up. Primary outcome is the level of paranoid ideations in daily life social situations, measured with ecological momentary assessments (EMA) at semi-random moments ten times a day during seven days, before and after treatment. Every session, participants and therapists will rate the level of paranoid ideation and global clinical impression.DiscussionComparison of VRcbt and CBTp will provide information about the relative (cost-) effectiveness of VRcbt for this population. VRcbt may become a preferred psychological treatment for paranoid delusions and social anxiety in patients with psychotic disorder.Trial registrationNetherlands Trial Register, NL7758. Registered on 23 May 2019.

Recalibrating expectations about effect size: A multi-method survey of effect sizes in the ABCD study.

Effect sizes are commonly interpreted using heuristics established by Cohen (e.g., small: r = .1, medium r = .3, large r = .5), despite mounting evidence that these guidelines are mis-calibrated to the effects typically found in psychological research. This study’s aims were to 1) describe the distribution of effect sizes across multiple instruments, 2) consider factors qualifying the effect size distribution, and 3) identify examples as benchmarks for various effect sizes. For aim one, effect size distributions were illustrated from a large, diverse sample of 9/10-year-old children. This was done by conducting Pearson’s correlations among 161 variables representing constructs from all questionnaires and tasks from the Adolescent Brain and Cognitive Development Study® baseline data. To achieve aim two, factors qualifying this distribution were tested by comparing the distributions of effect size among various modifications of the aim one analyses. These modified analytic strategies included comparisons of effect size distributions for different types of variables, for analyses using statistical thresholds, and for analyses using several covariate strategies. In aim one analyses, the median in-sample effect size was .03, and values at the first and third quartiles were .01 and .07. In aim two analyses, effects were smaller for associations across instruments, content domains, and reporters, as well as when covarying for sociodemographic factors. Effect sizes were larger when thresholding for statistical significance. In analyses intended to mimic conditions used in “real-world” analysis of ABCD data, the median in-sample effect size was .05, and values at the first and third quartiles were .03 and .09. To achieve aim three, examples for varying effect sizes are reported from the ABCD dataset as benchmarks for future work in the dataset. In summary, this report finds that empirically determined effect sizes from a notably large dataset are smaller than would be expected based on existing heuristics.

Psychological Response to the Diagnosis of Advanced Cancer: A Systematic Review

Despite major efforts to address psychological distress and quality of life (QOL) in people with cancer, only none to small intervention effect has been observed. There is reason to question whether psychosocial needs of patients have already been met under the usual oncology care. The purpose of this systematic review was to examine changes in depression, anxiety and QOL during the existential plight in advanced cancer. A literature search was performed in the PubMed and APA PsycINFO databases from year 1976 up to May 31, 2021. Longitudinal observational or experimental research targeting depression, anxiety or QOL in advanced cancer (stage III or IV), with baseline time since cancer diagnosis within 100 days, follow-up within 16 weeks post-baseline were eligible. Quality rating was based on the GRADE guidelines. Overall QOL did not reveal clinically relevant changes for the majority of studies as evaluated by effect size and raw score changes (median effect size 0.01, interquartile range -0.10-0.15). Nonetheless, modest to moderate improvement was found for depression (median effect size 0.28, interquartile range 0.03-0.38) and anxiety (median effect size 0.57, interquartile range 0.32-0.79). Transient distress symptoms and temporarily reduced functioning in the oncology setting may be considered normal, whereas impaired overall QOL needs to be addressed. Developing innovative interventions that enhance QOL for patients newly diagnosed with advanced cancer without interfering with patients' natural adaptation process is imperative.

Development and Cross-National Validation of a French Version of the Jefferson Scale of Empathy for Students.

Empathy is a multifaceted personal ability combining emotional and cognitive features modulated by cultural specificities. It is widely recognized as a key clinical competence that should be valued during professional training. The Jefferson Scale of Empathy for medical students (JSE-S) has been developed for this purpose and validated in several languages, but not in French. The aims of this study were to gather validity evidence for a newly developed version of the JSE-S and compare it between two French-speaking contexts. In total, 1,433 undergraduate medical students from the universities of Lyon (UL), France and Geneva (UG), Switzerland participated in the study completing the JSE-S in French. Total and partial scores of the three subscales (“perspective taking,” “compassionate care” and “walking in patient’s shoes”) were calculated for each site. Construct validity of the JSE-S was analyzed considering three sources of evidence: content, internal structure and relations to other variables. A first-order Confirmatory Factor Analysis using structural equation modeling examined the three latent variables of the JSE-S subscales. Cronbach’s α coefficients were 0.75 (UG) and 0.81 (UL). The items’ discrimination power ranged between 0.29 and 1.60 (median effect size of 1.24). The overall correlations between items and total or partial scores derived from the latent JSE-S subscales were consistently similar in both study sites. Findings of this study confirm the latent structure of the JSE-S in French and its cross-national reproducibility. The comparable underlying structure of the questionnaire tested in two distinct French-speaking contexts endorses the generalizability of its measure.

Bleuler revisited: on persecutory delusions and their resistance to therapy

Bleuler revisited: on persecutory delusions and their resistance to therapy

Improving implementation of school-based healthy eating and physical activity policies, practices, and programs: a systematic review.

Although best practice recommendations exist regarding school-based healthy eating and physical activity policies, practices, and programs, research indicates that implementation is poor. As the field of implementation science is rapidly evolving, an update of the recent review of strategies to improve the implementation of healthy eating and physical activity interventions in schools published in the Cochrane Library in 2017 was required. The primary aim of this review was to examine the effectiveness of strategies that aim to improve the implementation of school‐based policies, practices, or programs to address child diet, physical activity, or obesity. A systematic review of articles published between August 31, 2016 and April 10, 2019 utilizing Cochrane methodology was conducted. In addition to the 22 studies included in the original review, eight further studies were identified as eligible. The 30 studies sought to improve the implementation of healthy eating (n = 16), physical activity (n = 11), or both healthy eating and physical activity (n = 3). The narrative synthesis indicated that effect sizes of strategies to improve implementation were highly variable across studies. For example, among 10 studies reporting the proportion of schools implementing a targeted policy, practice, or program versus a minimal or usual practice control, the median unadjusted effect size was 16.2%, ranging from –0.2% to 66.6%. Findings provide some evidence to support the effectiveness of strategies in enhancing the nutritional quality of foods served at schools, the implementation of canteen policies, and the time scheduled for physical education.