What might be the cause of variability in effect sizes?5 answersVariability in effect sizes can stem from multiple sources. One significant factor is the presence of heterogeneity across studies, even in exact replications, indicating random variation beyond identifiable moderators. Additionally, the reconstructability of message variables in persuasive communication can influence the variability of effect sizes, posing challenges for theoretical advancements and message design. Moreover, the spread of variability in translational research, often unaccounted for, can drastically increase sample size requirements when progressing from preclinical to clinical studies. In the context of pain research utilizing current source density estimations, the lack of consensus on effect size magnitudes and variability highlights the importance of proper sample size calculations and effect size estimations for accurate study designs.
How do different statistical treatments affect the interpretation of results in quantitative research?5 answersDifferent statistical treatments can have a significant impact on the interpretation of results in quantitative research. One common issue is the inappropriate use of statistical power calculations after a study is completed and analyzed, particularly in the case of negative conclusions. Calculating observed power after the study can lead to incorrect interpretations, as a low observed power does not necessarily support the null hypothesis, but rather indicates that there were too few subjects. Another concern is the use of Null Hypothesis Significance Testing (NHST), which is often presented in terms of differences between groups and can lead to misconceptions about the research hypothesis. Additionally, the presence of treatment in genetic analyses can bias associations with quantitative traits, and the longitudinal nature of treatment trajectories needs to be properly accounted for. Ignoring the covariance between measurements in field studies can also lead to erroneous inference of treatment effects..
Can standardized coefficients be interpreted as effect sizes?4 answersStandardized coefficients can be used as effect sizes, but they can be difficult to interpret accurately. In one study, it was found that while effect sizes are commonly reported in standardized form, there is a high risk of misinterpretation. Another study focused on the use of standardized regression coefficients as an effect size index in meta-analysis. It provided practical recommendations for meta-analysts on how to estimate and convert standardized regression coefficients from original research articles. Additionally, a paper discussed the variance of standardized slopes as a desirable effect size measure for analyzing interactions between categorical and continuous variables. Another paper suggested using the probability of superiority as a more interpretable measure of effect size, particularly for paired or independent scores. Overall, while standardized coefficients can be used as effect sizes, it is important to consider the limitations and potential for misinterpretation.
How to analysis full mediation size?3 answersFull mediation can be analyzed using various methods. One approach is to use the bias-corrected percentile bootstrap method to analyze the mediator effect. Another method is to use the κ² or R2med index to measure full mediation, instead of using full and partial mediation. Confidence intervals for the population effect size should also be reported. It is important to consider the correlations between variables, measures of effect size, hypothesis testing, and confidence limit estimation when investigating mediation relations. However, κ² is not recommended as an effect size measure for mediation models due to its lack of rank preservation and potential for paradoxical results. It is also important to consider the specification of the estimated model and the distinction between full and partial mediation when analyzing mediation effects.
Why is the p-value necessary in Neuroscience, why not just judge it by the effect size?5 answersThe p-value is necessary in neuroscience because it provides a measure of the strength of evidence against the null hypothesis and helps in determining the significance of research findings. While effect size is important in understanding the practical significance of findings, it alone cannot provide a comprehensive understanding of the estimation of the difference calculated by null hypothesis significance testing. The p-value takes into account the sample size and allows researchers to reject or accept the null hypothesis based on statistical significance. Additionally, the p-value helps in assessing the association between variables, agreement between assessments, and time-trend, which cannot be determined by effect size alone. Therefore, both the p-value and effect size are important in neuroscience research, with the p-value providing a quantitative measure of statistical significance and effect size providing information about the practical significance of findings.
What are the sample size requirements for partial least squares structural equation modeling?5 answersPartial least squares structural equation modeling (PLS-SEM) can be effective with small sample sizes, but the appropriate sample size should be more significant than that generated by the rule-of-thumb methods. The findings suggest that a sample size of 50 is appropriate for PLS-SEM, with a power of 0.81 and an effect size (f2) ranging between 0.437 and 0.506. PLS-SEM is a nonparametric technique that makes no distributional assumptions and can be estimated with small sample sizes. Determining sample size requirements for PLS-SEM is a challenge, and commonly cited rules-of-thumb may not be accurate. Sample size requirements for PLS-SEM can vary depending on factors such as the number of indicators and factors, magnitude of factor loadings and path coefficients, and amount of missing data.