scholarly journals A meta-analysis of published semivariograms to determine sample size requirements for assessment of heavy metal concentrations at contaminated sites

Soil Research ◽  
2019 ◽  
Vol 57 (4) ◽  
pp. 311 ◽  
Author(s):  
L. E. Pozza ◽  
T. F. A. Bishop
Keyword(s):  
Sample Size ◽  
Meta Analysis ◽  
Contaminated Sites ◽  
Metal Concentrations ◽  
Second Stage ◽  
Guideline Value ◽  
Guideline Values ◽  
The Mean ◽  
A Site ◽  
Specific Metal

Soil contamination poses substantial risks to human and ecosystem health, justifying the need for accurate delineation and remediation of contaminated sites. The number of soil samples collected at a site during assessment is limited by cost and time available for assessment, increasing the potential for misclassification due to insufficient samples. Using distributions of heavy metals sourced from semivariograms provided in published studies, the first stage of this study sought to determine how many samples were required for the confidence interval around the mean to be above or below the Australian guideline value for each specific metal and study. Estimated sample size for assessing mean contamination across a site ranged from two to four samples; however, some distributions possessed a higher amount of variation and therefore required more samples. The second stage of the investigation explored sample size requirements for mapping contaminated sites. Unconditional Gaussian simulations created from published semivariograms were sampled using 15 different sample sizes, and the samples used to obtain predictions of the simulated distributions. For each sample, observed (simulated) and predicted (kriged) metal concentrations were classed as being below or exceeding the guideline values and compared through quantification of the number of misclassifications that occurred. When mapping a site of 5 km2 or less, uncertainty and misclassification decreased with increasing sample size, stabilising at around 200 samples; however, the lowest uncertainty occurred at around 500 samples. The study acknowledges this may be unrealistic and economically inefficient, so in addition to these findings it is worth exploring improvement in other areas of investigation, such as in the detection and mapping stages.

scholarly journals Systematic Review and Meta-Analysis of Fear of COVID-19

2021 ◽  
Vol 12 ◽  
Author(s):  
Faxiang Luo ◽  
Reza Ghanei Gheshlagh ◽  
Sahar Dalvand ◽  
Sholeh Saedmoucheshi ◽  
Qingyun Li
Keyword(s):  
Regression Analysis ◽  
Sample Size ◽  
Observational Studies ◽  
Meta Analysis ◽  
Target Population ◽  
Hospital Staff ◽  
Negative Effects ◽  
The Mean ◽  
Meta Regression ◽  
Meta Regression Analysis

Background: Due to lack of preparedness of health systems, fast spread of the new virus, high mortality rates, and lack of a definite treatment, the outbreak of Coronavirus disease (COVID-19) led to high levels of fear and anxiety in different populations. In addition, isolation, mental disorders, and limitations in social interactions as a result of lockdown and travel ban increased the fear of the new coronavirus.Methods: International databases, including Scopus, PubMed, Web of Science, and Google scholar, were searched without any time limitation, and all observational studies published in English reporting the mean of fear of COVID-19 based on the Fear of COVID-19 scale (FCV-19S) were included in the analysis. Methodological quality was assessed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. Random effects model, subgroup analysis, and meta-regression analysis were used to analyze the data. Heterogeneity across studies was examined using Cochran's Q test and I2 statistic. All the statistical analyses were conducted using R software v4.0.3.Results: A total of 44 articles with a sample size of 52,462 were reviewed. A pooled mean of 18.57 was found for fear of COVID-19. The mean of fear of COVID-19 was higher in women than in men (20.67 vs. 18.21). The highest and lowest means of fear of COVID-19 had been found in Asia (18.36) and Australia (17.43) based on continent, and in hospital staff (19.51) and college students (17.95) based on target population, respectively. In addition, the highest and lowest means of fear of COVID-19 were related to items #1 and #3 of the scale, respectively. According to the results of meta-regression analysis, there was no significant association between the mean of fear of COVID-19 and sample size and participants' age. In addition, publication error was not significant (P = 0.721).Conclusion: The mean of fear of COVID-19 was high around the world; therefore, it seems necessary to pay more attention to the negative effects of the COVID-19 pandemic on mental health.

Meta-Analysis of the Validity of a Verbal Ability Selection Test with Psychiatric Aides

1984 ◽  
Vol 54 (2) ◽  
pp. 676-678 ◽  
Author(s):  
M. K. Distefano ◽  
Margaret W. Pryer
Keyword(s):  
Sample Size ◽  
Meta Analysis ◽  
Verbal Ability ◽  
Small Samples ◽  
Selection Test ◽  
The Mean ◽  
The Individual ◽  
Over Time

This study demonstrated an application of Schmidt-Hunter meta-analysis procedures to cumulate validities from three studies with small samples of psychiatric aides obtained over time in a single organization. The mean correlation weighted for sample size between a verbal ability selection test and a job-relevant training criterion across samples ( N = 320) was .62 ( p < .01). The variance in the individual correlations was not significantly greater than that expected by chance, providing evidence that there was no true variation in obtained validities across samples.

scholarly journals Meta-Analysis Enables Prediction of the Maximum Permissible Arsenic Concentration in Asian Paddy Soil

2021 ◽  
Vol 9 ◽  
Author(s):  
Jajati Mandal ◽  
Sudip Sengupta ◽  
Soumyajit Sarkar ◽  
Abhijit Mukherjee ◽  
Michael D. Wood ◽  
...  
Keyword(s):  
Drinking Water ◽  
Decision Tree ◽  
Paddy Soil ◽  
Irrigation Water ◽  
Meta Analysis ◽  
Rice Grain ◽  
Rice Grains ◽  
Guideline Value ◽  
Guideline Values ◽  
The Relationship

It is now well-established that not just drinking water, but irrigation water contaminated with arsenic (As) is an important source of human As exposure through water-soil-rice transfer. While drinking water As has a permissible, or guideline value, quantification of guideline values for soil and irrigation water is limited. Using published data from 26 field studies (not pot-based experiments) from Asia, each of which reported irrigation water, soil and rice grain As concentrations from the same site, this meta-analysis quantitatively evaluated the relationship between soil and irrigation water As concentrations and the As concentration in the rice grain. A generalized linear regression model revealed As in soil to be a stronger predictor of As in rice than As in irrigation water (beta of 16.72 and 0.6, respectively, p &lt; 0.01). Based on the better performing decision tree model, using soil and irrigation water As as independent variables we determined that Asian paddy soil As concentrations greater than 14 mg kg−1 may result in rice grains exceeding the Codex recommended maximum allowable inorganic As (i-As) concentrations of 0.2 mg kg−1 for polished rice and 0.35 mg kg−1 for husked rice. Both logistic regression and decision tree models, identified soil As as the main determining factor and irrigation water to be a non-significant factor, preventing determination of any guideline value for irrigation water. The seemingly non-significant contribution of irrigation water in predicting grain i-As concentrations below or above the Codex recommendation may be due to the complexity in the relationship between irrigation water As and rice grains. Despite modeling limitations and heterogeneity in meta-data, our findings can inform the maximum permissible As concentrations in Asian paddy soil.

scholarly journals Statistical Significance Filtering Overestimates Effects and Impedes Falsification: A Critique of Endsley (2019)

2020 ◽  
Author(s):  
Jonathan Z Bakdash ◽  
Laura Ranee Marusich ◽  
Jared Kenworthy ◽  
Elyssa Twedt ◽  
Erin Zaroukian
Keyword(s):  
Sample Size ◽  
Situation Awareness ◽  
Meta Analysis ◽  
Statistical Significance ◽  
Effect Sizes ◽  
Quantitative Synthesis ◽  
The Mean ◽  
Meta Analyses ◽  
Filter Effects ◽  
Selection Of

Whether in meta-analysis or single experiments, selecting results based on statistical significance leads to overestimated effect sizes, impeding falsification. We critique a quantitative synthesis that used significance to score and select previously published effects for situation awareness-performance associations (Endsley, 2019). How much does selection using statistical significance quantitatively impact results in a meta-analytic context? We evaluate and compare results using significance-filtered effects versus analyses with all effects as-reported. Endsley reported high predictiveness scores and large positive mean correlations but used atypical methods: the hypothesis was used to select papers and effects. Papers were assigned the maximum predictiveness scores if they contained at-least-one significant effect, yet most papers reported multiple effects, and the number of non-significant effects did not impact the score. Thus, the predictiveness score was rarely less than the maximum. In addition, only significant effects were included in Endsley’s quantitative synthesis. Filtering excluded half of all reported effects, with guaranteed minimum effect sizes based on sample size. Results for filtered compared to as-reported effects clearly diverged. Compared to the mean of as-reported effects, the filtered mean was overestimated by 56%. Furthermore, 92% (or 222 out of 241) of the as-reported effects were below the mean of filtered effects. We conclude that outcome-dependent selection of effects is circular, predetermining results and running contrary to the purpose of meta-analysis. Instead of using significance to score and filter effects, meta-analyses should follow established research practices.

scholarly journals Statistical Significance Filtering Overestimates Effects and Impedes Falsification: A Critique of Endsley (2019)

2021 ◽  
Author(s):  
Jonathan Z Bakdash ◽  
Laura Ranee Marusich ◽  
Jared Kenworthy ◽  
Elyssa Twedt ◽  
Erin Zaroukian
Keyword(s):  
Sample Size ◽  
Situation Awareness ◽  
Meta Analysis ◽  
Statistical Significance ◽  
Effect Sizes ◽  
Quantitative Synthesis ◽  
The Mean ◽  
Meta Analyses ◽  
Filter Effects ◽  
Selection Of

Whether in meta-analysis or single experiments, selecting results based on statistical significance leads to overestimated effect sizes, impeding falsification. We critique a quantitative synthesis that used significance to score and select previously published effects for situation awareness-performance associations (Endsley, 2019). How much does selection using statistical significance quantitatively impact results in a meta-analytic context? We evaluate and compare results using significance-filtered effects versus analyses with all effects as-reported. Endsley reported high predictiveness scores and large positive mean correlations but used atypical methods: the hypothesis was used to select papers and effects. Papers were assigned the maximum predictiveness scores if they contained at-least-one significant effect, yet most papers reported multiple effects, and the number of non-significant effects did not impact the score. Thus, the predictiveness score was rarely less than the maximum. In addition, only significant effects were included in Endsley’s quantitative synthesis. Filtering excluded half of all reported effects, with guaranteed minimum effect sizes based on sample size. Results for filtered compared to as-reported effects clearly diverged. Compared to the mean of as-reported effects, the filtered mean was overestimated by 56%. Furthermore, 92% (or 222 out of 241) of the as-reported effects were below the mean of filtered effects. We conclude that outcome-dependent selection of effects is circular, predetermining results and running contrary to the purpose of meta-analysis. Instead of using significance to score and filter effects, meta-analyses should follow established research practices.

scholarly journals Statistical Significance Filtering Overestimates Effects and Impedes Falsification: A Critique of Endsley (2019)

2020 ◽  
Vol 11 ◽  
Author(s):  
Jonathan Z. Bakdash ◽  
Laura R. Marusich ◽  
Jared B. Kenworthy ◽  
Elyssa Twedt ◽  
Erin G. Zaroukian
Keyword(s):  
Sample Size ◽  
Situation Awareness ◽  
Meta Analysis ◽  
Statistical Significance ◽  
Effect Sizes ◽  
Quantitative Synthesis ◽  
The Mean ◽  
Meta Analyses ◽  
Filter Effects ◽  
Selection Of

Whether in meta-analysis or single experiments, selecting results based on statistical significance leads to overestimated effect sizes, impeding falsification. We critique a quantitative synthesis that used significance to score and select previously published effects for situation awareness-performance associations (Endsley, 2019). How much does selection using statistical significance quantitatively impact results in a meta-analytic context? We evaluate and compare results using significance-filtered effects versus analyses with all effects as-reported. Endsley reported high predictiveness scores and large positive mean correlations but used atypical methods: the hypothesis was used to select papers and effects. Papers were assigned the maximum predictiveness scores if they contained at-least-one significant effect, yet most papers reported multiple effects, and the number of non-significant effects did not impact the score. Thus, the predictiveness score was rarely less than the maximum. In addition, only significant effects were included in Endsley’s quantitative synthesis. Filtering excluded half of all reported effects, with guaranteed minimum effect sizes based on sample size. Results for filtered compared to as-reported effects clearly diverged. Compared to the mean of as-reported effects, the filtered mean was overestimated by 56%. Furthermore, 92% (or 222 out of 241) of the as-reported effects were below the mean of filtered effects. We conclude that outcome-dependent selection of effects is circular, predetermining results and running contrary to the purpose of meta-analysis. Instead of using significance to score and filter effects, meta-analyses should follow established research practices.

Response Rates in Online Surveys With Affective Disorder Participants

2020 ◽  
Vol 228 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Tanja Burgard ◽  
Michael Bošnjak ◽  
Nadine Wedderhoff
Keyword(s):  
Meta Analysis ◽  
Response Rates ◽  
Contact Mode ◽  
General Anxiety Disorder ◽  
General Anxiety ◽  
Face To Face ◽  
Survey Participation ◽  
The Mean ◽  
Design Characteristics ◽  
E Mail

Abstract. A meta-analysis was performed to determine whether response rates to online psychology surveys have decreased over time and the effect of specific design characteristics (contact mode, burden of participation, and incentives) on response rates. The meta-analysis is restricted to samples of adults with depression or general anxiety disorder. Time and study design effects are tested using mixed-effects meta-regressions as implemented in the metafor package in R. The mean response rate of the 20 studies fulfilling our meta-analytic inclusion criteria is approximately 43%. Response rates are lower in more recently conducted surveys and in surveys employing longer questionnaires. Furthermore, we found that personal invitations, for example, via telephone or face-to-face contacts, yielded higher response rates compared to e-mail invitations. As predicted by sensitivity reinforcement theory, no effect of incentives on survey participation in this specific group (scoring high on neuroticism) could be observed.

The Effect of Desmopressin on Reducing Blood Loss in Cardiac Surgery – A Meta-Analysis of Double-Blind, Placebo-Controlled Trials

1995 ◽  
Vol 74 (04) ◽  
pp. 1064-1070 ◽  
Author(s):  
Marco Cattaneo ◽  
Alan S Harris ◽  
Ulf Strömberg ◽  
Pier Mannuccio Mannucci
Keyword(s):  
Cardiac Surgery ◽  
Blood Loss ◽  
Meta Analysis ◽  
Postoperative Blood Loss ◽  
Controlled Trials ◽  
Double Blind ◽  
Double Blind Placebo ◽  
Transfusion Requirements ◽  
The Mean ◽  
Excessive Blood Loss

SummaryThe effect of desmopressin (DDAVP) on reducing postoperative blood loss after cardiac surgery has been studied in several randomized clinical trials, with conflicting outcomes. Since most trials had insufficient statistical power to detect true differences in blood loss, we performed a meta-analysis of data from relevant studies. Seventeen randomized, double-blind, placebo-controlled trials were analyzed, which included 1171 patients undergoing cardiac surgery for various indications; 579 of them were treated with desmopressin and 592 with placebo. Efficacy parameters were blood loss volumes and transfusion requirements. Desmopressin significantly reduced postoperative blood loss by 9%, but had no statistically significant effect on transfusion requirements. A subanalysis revealed that desmopressin had no protective effects in trials in which the mean blood loss in placebo-treated patients fell in the lower and middle thirds of distribution of blood losses (687-1108 ml/24 h). In contrast, in trials in which the mean blood loss in placebo-treated patients fell in the upper third of distribution (>1109 ml/24 h), desmopressin significantly decreased postoperative blood loss by 34%. Insufficient data were available to perform a sub-analysis on transfusion requirements. Therefore, desmopressin significantly reduces blood loss only in cardiac operations which induce excessive blood loss. Further studies are called to validate the results of this meta-analysis and to identify predictors of excessive blood loss after cardiac surgery.

scholarly journals Outcomes of Oblique Lateral Interbody Fusion for Adult Spinal Deformity: A Systematic Review and Meta-Analysis

2021 ◽  
pp. 219256822097914
Author(s):  
Lei Zhu ◽  
Jun-Wu Wang ◽  
Liang Zhang ◽  
Xin-Min Feng
Keyword(s):  
Systematic Review ◽  
Lumbar Lordosis ◽  
Interbody Fusion ◽  
Perioperative Complications ◽  
Adult Spinal Deformity ◽  
Meta Analysis ◽  
Fusion Rate ◽  
The Mean ◽  
Oblique Lateral Interbody Fusion ◽  
Lateral Interbody

Study Design: A systematic review and meta-analysis. Objectives: To evaluate clinical and radiographic outcomes, and perioperative complications of oblique lateral interbody fusion (OLIF) for adult spinal deformity (ASD). Methods: We performed a systematic review and meta-analysis of related studies reporting outcomes of OLIF for ASD. The clinical outcomes were assessed by visual analogue scale (VAS) and Oswestry Disability Index (ODI). The radiographic parameters were evaluated by sagittal vertical axis (SVA), pelvic tilt (PT), sacral slope (SS), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence-lumbar lordosis (PI-LL), Cobb angle and fusion rate. A random effects model and 95% confidence intervals (CI) were performed to investigate the results. Results: A total of 16 studies involving 519 patients were included in the present study. The mean difference of VAS-back score, VAS-leg score and ODI score before and after surgery was 5.1, 5.0 and 32.3 respectively. The mean correction of LL was 20.6°, with an average of 6.9° per level and the mean correction of Cobb was 16.4°, with an average of 4.7° per level. The mean correction of SVA, PT, SS, TK and PI-LL was 59.3 mm, 11.7°, 6.9°, 9.4° and 20.6° respectively. The mean fusion rate was 94.1%. The incidence of intraoperative and postoperative complications was 4.9% and 29.6% respectively. Conclusions: OLIF is an effective and safe surgery method in the treatment of mild or moderate ASD and it has advantages in less intraoperative blood loss and lower perioperative complications.

scholarly journals Outpatient Total Hip Arthroplasty: A Meta-Analysis

2021 ◽  
Vol 11 (15) ◽  
pp. 6853
Author(s):  
Filippo Migliorini ◽  
Lucio Cipollaro ◽  
Francesco Cuozzo ◽  
Francesco Oliva ◽  
Andrea Valerio Marino ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Meta Analysis ◽  
Readmission Rates ◽  
Total Hip ◽  
Vein Thrombosis ◽  
Outpatient Group ◽  
Operative Planning ◽  
The Mean ◽  
And Gender

Introduction: Outpatient total hip arthroplasty (THA) is increasingly popular. This meta-analysis investigated the potential advantages of outpatient regimes for THA. Methods: This study followed the PRISMA guidelines. PubMed, Web of Science, Google Scholar, Embase, and Scopus databases were accessed in June 2021. All clinical studies investigating outpatient THA were considered. The outcomes of interest were pain, infection, mortality, revision, dislocation, readmission rates, and deep vein thrombosis (DVT). Results: Data from 102,839 patients were included. A total of 52% (153,168 of 102,839 patients) were women. The mean age of patients was 62.6 ± 4.6 years, the mean BMI was 29.1 ± 1.8 kg/m2. Good comparability was found in age, BMI, and gender (p > 0.1). No difference was found in pain (p = 0.4), infections (p = 0.9), mortality (p = 0.9), rate of revision (p = 0.1), dislocation (p = 0.9), and readmission (p = 0.8). The outpatient group demonstrated a greater rate of DVT (OR 3.57; 95% CI 2.47 to 5.18; p < 0.0001). Conclusions: In selected patients, outpatient THA can be performed safely with optimal outcomes comparable with inpatient THA. Clear and comprehensive pre-operative planning should involve a multi-disciplinary group composed of orthopaedic surgeons, anaesthesia and rehabilitation specialists, and physiotherapists. Each centre performing outpatient THA should implement continuous homecoming welfare activity, to supervise physiotherapy and monitor anticoagulant therapy.

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