Questions tagged [effect-size]
Effect size is "a measure of the strength of a phenomenon or a sample-based estimate of that quantity" [Wikipedia].
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What is the relationship between effect size and noise?
I understand that noise in measurement can affect the size of an observed effect. That noise can result in larger measurement error, which can reduce the size of the observed effect. However, I do not ...
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Can you meta-analyze multiple outcomes of a single experiment?
Suppose there is an experimental design where the test participant is randomly assigned to 1 of 3 conditions (1 control, 1 treatment, 1 placebo).
Each participant then completes 6 different measures ...
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Is it possible to summarise standardized mean differences deriving from different variables in a meta-analysis?
I am conducting a meta-analysis on the alteration of fine roots in forest soil as a consequence of soil compaction after logging operations. I have already the database which is made up of studies ...
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What's the appropriate effect size estimate (and power analysis) for post-hoc regression?
I've seen some similar (ex ex2) questions, but hopefully this is not a duplicate. As it is mentioned in one of them, I'm using eemmeans to do pairwise comparisons ...
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Is performing statistical test on t-values or z-scores themself valid?
I wonder if it is valid to perform a statistical test on t-values or z-scores. For instance, if one gets two groups of t-values, every t-value is generated from an individual t-test and the value ...
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Calculating relative effect size with standard mean difference and 95%CI
I have effect size (standard mean difference) and 95%CI for a meta-analysis. How can I calculate the relative effect size using this information? Other information I have includes pooled SD for ...
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Summarizing ratios in a systematic review - does any joint effect measure exist?
I am responding to reviewer comments on a systematic review summarizing a number of risk factors. The exposure is any risk factor (this is what I am trying to make an overview of) and the outcome is ...
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Meta-Analysis: Effect size calculation from test statistics (within subject)
I am trying to conduct a quantitative meta-analysis on an effect measured within subjects. I am currently facing the issue that I don't have any means or SD, but only F- and t-statistics, but I'd like ...
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How to calculate effect size when I have the mean difference, CI of that mean difference and n?
Any advice without using any coding software would be appreciated - thanks!
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Power analysis for two-way repeated measures ANOVA
I am trying to run a post-hoc power analysis on a previously conducted study, in which the results were analysed through a two-way repeated measures ANOVA (I used a 2x2 within-subjects design). ...
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Can I compare a Cohen's d to a log-response ratio in a meta-analysis?
I'm conducting a meta-analysis and I'm wondering if I can make direct comparisons between different types of effect sizes? For example, can I compare a Cohen's d calculated from one study to a log-...
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Power analysis for Generalized Linear Model with gamma family and log link in R
I have a data set with 360 observations. I run a glm with a gamma family, and I want to show that I fail to reject the null hypothesis. Although the p-value greater than 0.05 is kind of showing that ...
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Pooled standard deviation of two correlated variables [closed]
I'm trying to calculate an effect size index where I need to pool 2 standard deviations calculated from correlated variables (pre-post treatment scores). Using the standard formula:
$$
\sigma^2_{...
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effect size for paired t test
I have question regarding effect size for paired t test
some textbooks and statistical software like spss use this formula
Cohen′sd = d/SDofdifference
to calculate effect size for paired t test and ...
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Should a meta-analysis of group differences calculate Hedges’ G separately for each group, or calculate Hedges' G for the group difference?
I am reading a meta-analysis where the authors state the following. (I've redacted the active drug name, as my purpose is to understand not call anyone out.)
The treatment response to placebo and [...
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Modelling predictor as quadratic term lowers BIC but marginal effect plot shows linear distribution?
I am using a modified Hosmer Lemeshaw approach, culminating in all possible combinations model selection, to conduct multiple logistic regression that should distinguish between use (1) and available ...
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How can delta (Δ) R² for a term be larger than R² for that term?
I am testing whether a variable predicts an outcome - firstly on its own, and then after controlling for various covariates. Since the outcome is continuous, I want to report R² as an effect size ...
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How do I convert probability standard error to log odds standard error?
I am conducting a meta-analysis of individual studies that report probabilities and their standard error as an effect size. I plan to convert the probabilities and standard errors to the natural ...
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How to interpret a small regression coefficient with a p-value of 0.01 in an OLS model?
I have built a multiple regression and estimated it using OLS. All the variables are significant. One of the coefficients is close to zero (around 0.0003) with a significant p-value of 0.01. How to ...
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Calculating effect size of wilcoxon test after correction for multiple comparisons using R
I am trying to compare two amino acid concentrations after two treatment variations. The data is not normal distributed, so I have to use non-parametric tests. I calculated the adjusted p values, but ...
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Help with conducting a priori power analysis to estimate sample size
Hy, I am replicating a study that looked into the effect that role models have on inspiration.
I am required to do a a priori power analysis to estimate what the minimum sample size would be needed. ...
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Compute minimum detectable effect in multiple logistic regression
I would like to calculate what effect size a given sample size, in a multiple logistic regression, is sensitive to detect.
Do you have any advice? Is there a way in R?
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How to Simulate T-Values for Two Different Samples
Motivating Question
I had a discussion with somebody recently, who said that a 10 participant sample with a t-value of 2.1 is more impressive than the same t-value for a 100 participant sample. The ...
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Semipartial correlation and logistic regression
I am running a series of multiple linear regression models as well as logistic regression models. I have calculated the semipartial correlations (sr) as a measure of effect size for the linear ...
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Is there a poisson variant for cohen's D/ Hedges' G?
I've got a problem with some count data of mine.
I am using a cohen's D/ Hedges G to compare the effect size between two different treatment groups in my experiment, and then repeating that process ...
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Power paradox: overestimated effect size in low-powered study, but the estimator is unbiased
If we have an underpowered study but manage to reject the null hypothesis, anyway, it makes sense to wonder if we have overestimated the effect size.
However, such a concern seems unwarranted if we ...
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How to compare effects of predictors between GAMs?
I have two models, which share some predictors. I'd like to compare the magnitude of their effects on the respective response variable.
Here's an example based on data and code taken from here.
Data:
<...
user293815
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Comparing effect sizes of two covariates each in their own (but otherwise identical) GAM
Can anyone point me to sources (publications, blog posts, videos etc) about the following problem? (The more conceptual the discussion, the better!)
I have the two explanatory GAMs below (in this ...
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Meta analysis of quantile regressions in a mixed model approach
I want to test if lower quantiles lead to lower effect sizes of quantile regressions. The regressions were made across different, nested, contexts. Specifically, I made correlations for 3 percentiles (...
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Bootstrapping to Overcome Power Concern with ANOVA?
all,
I just conducted the power analysis for a lab study I am hoping to run soon. The main idea is comparing the difference in means across three conditions with a balanced one-way ANOVA (see image ...
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Comparing Cohen's D and Arcsine Transformation in Meta-analysis
I'm conducting a meta-analysis that consists of 15 studies and ~40 construct effect sizes. Most of the constructs and studies use continuous variables and were straightforward in finding standardized ...
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Use of ratio of means effect measure and estimation of variance from mean of ratios
I am running a meta-analysis where we are using the ratio of means (RoM) effect measure as the data we are using compare the two sides of the body (i.e. left and right). All RoM calculations are ...
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effect vs significance
I've seen on some plots e.g. with values for the statistical of significance p = 0.7 and for the effect size of g = 0.5.
Is it possible to say there is a certain effect (size) when it is not ...
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Converting Cohen's $d$ to Pearson's $r$ $\ne$ calculated Pearson's $r$
I was calculating effect sizes for an analysis and noticed by chance that Pearson's $r$ calculated from Cohen's $d$ with a conversion formula is not the same as when I calculate the correlation given ...
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effect sizes from stepwise regression
I'm new to stepwise regression and I've been asked to conduct one for my boss. In doing so, they also asked for the effect sizes from each predictor in the model. Disregarding any debates around ...
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Meta analysis for a number of identical studies (with access to raw data)
I have access to about ten almost identical studies from ten different locations.
They have been done different years, but with the same methodology.
Each site was analysed and reported separately ...
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How do I use beta in meta-analysis?
I am completely new to meta analyses and I have to do one for a university project.
I basically have beta coefficients from different papers performing covariate methods such as partial least squares, ...
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What is the difference between Partial Eta Squared and Partial R Squared in factorial repeated ANOVA?
I carried out an repeated measures ANOVA in SPSS with two within subjects predictors, and requested for measures of effect size.
SPSS provides partial Eta Squared as a measure of effect size, but I ...
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Can I compare the confidence interval when having small sample sizes?
I ran an experiment in which I calculated the biomass of 2 treatments - say A and B. Each treatment had 4 replicates. I now would like to calculate
the 95% confidence intervals of the mean biomass of ...
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Interpretation of coefficients in GLM: coefficients associated to continuous covariates interpreted as MD's or OR's
I was having a discussion with someone regarding OR’s estimated trough a logistic regression and then he claims that OR’s for continuous variables can only be estimated trough a logistic regression. ...
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Effect sizes for pre-post control design but with uneuqal pre-post sample sizes?
I am trying to compute the effect sizes for the pre-post control design studies. Here is what I found in Morris (2018) and I quote
"For the PPC design, three effect size estimates have been ...
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Calculate SE of odds ratio for meta-analysis without 95% CI or p-value
I'm working on a meta-analysis and one study provides odds ratios without standard errors, confidence intervals or exact p-values.
The only information provided is odds ratios, whether the p-value was ...
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Effect size and confidence interval for difference in two regression coefficients
I have an effect size that is a difference between two regression coefficients $\Delta\beta=\beta_a-\beta_b$. The response and predictor units are the same in each model, and the question relates ...
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Which coefficient is correct for assessing effect size of a regression interaction, standardized or unstandardized?
My team is conducting a healthcare regression analysis and is interested in both the p-value and the magnitude of an interaction coefficient (i.e., effect size). For our project we want p-value < ....
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Using p-values as an effect size measure [closed]
In the following circumstance, I believe it is valid to use p-values as a measure of effect size: am I wrong?
I have a set of objects which have a single 'observed distance' from a given spatial ...
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Meta-Analysis help with next steps
I am conducting a meta-analysis on literature that is comparing two platforms to each other. I've extracted statistics from the relevant comparison and for the relevant dvs (response time, accuracy). ...
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Interpreting the effect size for a categorical response variable, when the exploratory variable is also categorical
Please find the following reproducible code in R.
...
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Effect Size for Wilcoxon-Mann-Whitney in R Cohen's d
I have a non-normal distribution data of two independent samples of patients divided by two groups 'control' and 'treatment'. I would like to verify if there is a difference between the two groups '...
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What is effect size?
It might be silly question-want to have clarity of this concept.I was wondering if someone can elaborate meaning and examples of effect size in clinical research. How to interpret it accurately? How ...
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sum of classic eta squared greater than 1
I know that in an ANOVA with multiple factors (let's say x1 and x2), the sum of their respective classic eta squared (not 'partial' eta squared) cannot be greater than one and should approximate the ...
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