# 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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### Computing effect size (d) for lmer() in R

I have selected to compute the Cohen's d effect size for the fixed effects of my linear mixed model. However, it's a little unclear why I'm getting the results I am. First, I am using the method ...
29 views

### Derivative-based effect size for Gaussian GAMs

It is often the realistic advice I have seen here that Gaussian GAMs are not regressions with which you can easily approximate an effect size for, as the effects are of course non-linear. However, we ...
16 views

### Ratio of odds ratio to Cohen d

If I have two binary predictors and a binary response how can we calculate the effect size of the interaction term. I use logistic regression from statsmodels package in python. Will it be ratio of ...
38 views

### Is it possible to perform a meta-analysis of multiple outcomes and multiple predictors?

I have a pool of 20-ish quantitative studies that report odds ratios for a particular outcome (e.g. homelessness) but most studies will also report a few more outcomes. All of these studies report the ...
21 views

### Wilcoxon test for mixed data

I have gameplay data of 20 patients, some is following normal distribution and some is following non normal distribution, so I used Wilcoxon test to identify if there is significant change in speed in ... 1 vote
14 views

### Multiple group analysis in canonical correlation analysis

Canonical correlation analysis estimates the relationship between two canonical sets of variables. However, I am interested in using a technique to compare these CCA results across groups (something ...
1 vote
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### Can I create effect sizes from published reports without access to the data? Thinking about standardizing unstandardized coefficients?

I'm reviewing and synthesizing 48 published articles on the same topic (association between x and y). Instead of describing findings based on statistical significance and power, I'd like to be able to ...
1 vote
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### How to measure the increase in violent crime between years?

I have crime data from my country, consisting of the counts of recorded crimes (split by various categories), as well as population data from census years. I want to measure if there has been a ...
39 views

### Effect size in multiple logistic regression

I have one dummy independent variable, one categorical independent variable with six categories, and two continuous independent variables. The dependent variable is binary (yes/no). The interaction ...
25 views

### Computing the effect size of a Level 2 predictor in HLM

I am looking for advice on computing effect sizes for Level 2 predictors in HLM models. I found this documentation: https://ssicentral.com/wp-content/uploads/2020/07/FAQ_Effect_sizes.pdf, but am ...
42 views

### calculate effect size from regression table

I am working on power analysis for a project. I want to benchmark effect size from another study. How can I find the effect size (Cohen's d) just by looking at the regression table below? For instance,...
28 views

### Effect-size of a fractional factorial design?

Let us assume I conduct an experiment, in which the participants perform four different tasks, getting a tool support or not. We measure the time to complete each task, either with the support of a ...
50 views

### Improve estimation of effect-size (difference between two distributions) by using LDA distance to decision boundary

Before getting to the point, I will provide some context: I have a dataset that includes $176$ quantitative neuroimaging markers ($m_i$ for $i=1,...,176$) and several categorical variables ...
22 views

### How to transform GEE coefficients to Cohen's d (standardized mean difference) for meta-analysis

I am conducting a meta analysis and am looking into how to convert coefficients (with SEs) from a GEE linear estimation into a standardized mean difference, Cohen's d. Does anyone have any hints on ...
54 views

### Determining the effect of two coefficients combined when the model includes an interaction term

Imagine I'm trying to model traffic stops with a logistic regression. ...
104 views

### Calculation of standard deviation of the mean changes from the p-value or z-value of the Wilcoxon test

I am conducting a meta-analysis of observational studies without a control group that compared a parameter's value before and after an operation. All included studies have reported their results as ...
19 views

### Is the mean difference between two groups a relative treatment effect?

In randomized trials, I know that treatment effects such as the odds ratios, relative risks and hazard ratios are considered relative treatment effects. What about the following effect sizes? a. Mean ...
104 views

### Is the Neyman-Pearson paradigm for hypothesis testing adequate in the social sciences, and if not, is calculating a priori power still adequate?

I'm reading about Fisherian vs. Neyman-Pearson paradigms relative to hypothesis/significance testing. (NB: I'm new to this and self-studying it, so I'd be glad to be corrected if I misinterpret ...
72 views

### G*Power ANOVA repeated measures within-between interaction

I'd love to get a sanity check on a sample size calculation I'm running in G*Power. I'm planning a study with 2 groups and 2 measurement points, aiming for a f of 0.10 because, to my understanding, it'...
1 vote
67 views

### Computing Cohen's D directly from a Welch's t statistic

I'm performing a meta-analysis and am trying to extract a Cohen's $\hat{d}$ effect size measure from a paper; however the paper does not report any means or SDs. They do, however, report the results ...
27 views

### How can I directly compare the effects of a predictor on a continuous and a dichotomous dependent variable?

I want to assess how a predictor differs in its associations with 2 different dependent measures (i.e., a continuous measure of objective memory and a categorical measure of self-rated memory). I also ...
42 views

### How to calculate effect size to to use Power Analysis to get minimum sample size when standard deviation is not available (digital marketing AB test)?

TLDR: I can't find a way to calculate the effect size needed to be inputted to Power Analysis to get the minimum sample size needed to 90% statistical significance as I can't calculate standard ...
1 vote
28 views

### How to calculate the effect sizes for a meta-analysis if a RCT study reported the correlation coefficient using partial pearson corrleation analysis?

I am currently performing a meta-analysis focusing on investigating the changes in variable A following weight loss. To address this, I have included studies that provide pre-and post-intervention A ...
22 views

### Intrasubject coefficient of variation for cross-over sample size calculation

I would like to calculate the required sample size for a crossover design based on a study conducted in a parallel-design. I understand that one needs the within subject CV. Unfortunately, the authors ...
24 views

### General interpretations of permutation null distributions under the alternative

I've come across some papers employing z-scores of permutation null distributions as a primary metric in neuroscience (for an example, see here). The authors computed a coefficient of interest in a ...
1 vote
79 views

### How to calculate effect size based on percentage and sample size?

In an intervention study, I have the following information - % of students passing an exam pre- and post intervention, sample size for control group and intervention group at pre- and post ...
21 views

### How to translate calculated Effect size into original units of measurement?

I am running a hypothesis test, and I am trying to share the statistics on this test to business user. I have calculated effect size using Cohen's d. Now I want to find a way to convert this effect ...
28 views

### How to account for difference in group sizes for logistic regression

Using this study as an example, I am wondering if the size of different study groups run in the same models impacts the conclusions we can draw from statistical tests. In this study, the researchers ...
1 vote
26 views

### meta-analysis when the control value is taken from a standard (iso, en, etc...) and do has not any variance

I am starting to conduct a meta-analysis on the effect of different raw materials on pellets quality (for bioenergy purposes) I have already the database of studies and my idea initially was to ...
1 vote
23 views

### How to find Cohen's f for multiple regression with interaction included?

I am currently investigating the moderating role of mindfulness in the association between academic distress and suicide ideation with depression as a control variable. I finished doing the multiple ...
1 vote
80 views

### Conducting power analysis to minimize number of tests: generalized linear model (GLZ) with binary outcome, zero inflated binomial predictors R

My problem: I have a fixed, imbalanced, case-control cohort where I am using two (2) low occurrence predictors (rare variants) to try to find an association between the predictors and disease. I will ...
50 views

### Statistical power of an experiment calculation

As titled,I had some confusion related to statistical power calculation. The calculation is done using ...
167 views

### Convert Cohen's d to nonparametric effect size and use as equivalence bounds

In a within-subjects design (n = 30), I had planned to run equivalence tests with the equivalence bounds set at the effect size of Cohen's d 0.35. This is partly based on previous research and partly ...
38 views

### Why is it important to correct for correlated (dependent) measures when reporting Cohen's d?

I am calculating within-group effect sizes from pre-test to post-test. Cohen's dav reports this effect size as a proportion of the average standard deviation (Lakens, 2013): Meanwhile, Cohen's drm ...
112 views

### Determine the sample size to validate a bug fix

Using gpower, I would like to calculate the sample size to validate a bug fix. There is a software bug that appears in 3 out of 1000 test runs. I would like to validate a bug fix so that it doesn't ...
136 views

### Pairwise Effect size for Dunns Test

I am using ggsttaplot - I am curious how to get effect size for each pair: ...
285 views

### How to calculate effect size of moderation analyses on repeated-measures data?

I conducted a moderation analysis on repeated-measures data using the MEMORE macro for SPSS (https://www.akmontoya.com/spss-and-sas-macros). However, I need standardized effect sizes but I haven't ...
39 views

### Effect size for comparing two models using anova(test="Chisq") function in R

How do I get the effect size (e.g., Cohen's w) for a comparison of two models using anova(lm.1,lm.2,test="Chisq") function in ...
63 views

### Can high standard deviations explain my non-significant & low effect size results? (please read description)

I'm trying to analyse bullying experiences across three age groups. The DV is scored on a 5-point Likert, and the IV is categorical (ages 11, 13, and 15). Initially I ran an ANOVA to see if there was ...
158 views

### Glass' delta effect size when there is no control or pre-measurement group

Cohen's d and Hedges'g effect sizes are used when two distributions have equal variances, which is a requirement and assumption to use these statistical tests. When two distributions have unequal ...
128 views

### One Sample Wilcoxon effect size

I am struggling with effect size calculations for the Wilcoxon test for one sample in R. My data: item1 <- c(1,5,3,4,4,2,3,2,1,4,5,4,3,1) ...
327 views

### Calculate effect size Cohen's w (omega) for a chi-square test in model comparison

I have two logistic mixed-effects models, nested within each other and differing in only one fixed variable: ...
30 views

### compute expected effect size from n

In most scenarios power calculations are used to determine n, given expected effect size, power and significance level. However, if I already know ...
132 views

### Is post-hoc power analysis redundant too in the case of a *significant* result? [duplicate]

I've read that post-hoc power analysis is useless when the result of a test is statistically insignificant, which I understand (post-hoc power analysis is just circular logic in this scenario). But ...
1 vote
20 views

### Is there a statistical approach to determine the minimum sample size for comparison of sums over time?

I have the number of items sold of various products over time from a supermarket. Each product belongs to a category of products. Some categories have a large number of items sold and some categories ...
36 views

### Standardized dependent variable, effect size interpretation

I have the following model: RT ~ condition + (1|participant) RT is a continuous variable. Condition has three levels and is coded using Helmert contrasts. I ...
67 views

### Can you explain me how critical value can be included in this equation of the minimum detectable size?

According to the theory, power is 1-beta which is the probability of not rejecting the null hypothesis when this one is false. Then power uses the alternative hypothesis distribution. The minimum ...
1 vote
49 views

### Sample size and power analysis: Chi-square

Can someone help with a sample size analysis question? Study design: I have a sample randomly assigned to answer 1 of 5 different questions that vary in difficulty (1 - Easy -> 5 - Hard). The ...
1 vote
I would like to determine a partial correlation from fixed effects in my linear mixed models. If i would run a model for example $Aij = \beta_0 + \beta_1X + \beta_2Y + \beta_2Z + ui$ + ϵij Can I ...