effectsize: Indices of Effect Size 
Significant is just not enough!
The goal of this package is to provide utilities to work with indices of effect size and standardized parameters, allowing computation and conversion of indices such as Cohen’s d, r, odds-ratios, etc.
Installation
Run the following to install the stable release of effectsize from CRAN:
install.packages("effectsize")Or you can install the latest development version from R-universe:
install.packages("effectsize", repos = "https://easystats.r-universe.dev/")Documentation
Click on the buttons above to access the package documentation and the easystats blog, and check-out these vignettes:
- Effect Sizes
- Effect Sizes Conversion
- Automated Interpretation of Indices of Effect Size
Features
This package is focused on indices of effect size. Check out the package
website for a full list of features and functions provided by
effectsize.
library(effectsize)
options(es.use_symbols = TRUE) # get nice symbols when printing! (On Windows, requires R >= 4.2.0)Tip:
Instead of
library(effectsize), uselibrary(easystats). This will make all features of the easystats-ecosystem available.To stay updated, use
easystats::install_latest().
Effect Size Computation
The package provides functions to compute indices of effect size.
Standardized Differences (Cohen’s d, Hedges’ g, Glass’ delta)
cohens_d(mpg ~ am, data = mtcars)
## Cohen's d | 95% CI
## --------------------------
## -1.48 | [-2.27, -0.67]
##
## - Estimated using pooled SD.
hedges_g(mpg ~ am, data = mtcars)
## Hedges' g | 95% CI
## --------------------------
## -1.44 | [-2.21, -0.65]
##
## - Estimated using pooled SD.
glass_delta(mpg ~ am, data = mtcars)
## Glass' Δ | 95% CI
## -------------------------
## -1.17 | [-1.93, -0.39]effectsize also provides effect sizes for rank tests, common
language effect sizes and more…
Contingency Tables
# Dependence
phi(mtcars$am, mtcars$vs)
## ϕ (adj.) | 95% CI
## -----------------------
## 0.00 | [0.00, 1.00]
##
## - One-sided CIs: upper bound fixed at [1.00].
cramers_v(mtcars$am, mtcars$cyl)
## Cramer's V (adj.) | 95% CI
## --------------------------------
## 0.46 | [0.00, 1.00]
##
## - One-sided CIs: upper bound fixed at [1.00].
# Goodness-of-fit
fei(table(mtcars$cyl), p = c(0.1, 0.3, 0.6))
## פ | 95% CI
## -------------------
## 0.27 | [0.17, 1.00]
##
## - Adjusted for non-uniform expected probabilities.
## - One-sided CIs: upper bound fixed at [1.00].ANOVAs (Eta2, Omega2, …)
model <- aov(mpg ~ factor(gear), data = mtcars)
eta_squared(model)
## # Effect Size for ANOVA
##
## Parameter | η² | 95% CI
## ----------------------------------
## factor(gear) | 0.43 | [0.18, 1.00]
##
## - One-sided CIs: upper bound fixed at [1.00].
omega_squared(model)
## # Effect Size for ANOVA
##
## Parameter | ω² | 95% CI
## ----------------------------------
## factor(gear) | 0.38 | [0.14, 1.00]
##
## - One-sided CIs: upper bound fixed at [1.00].
epsilon_squared(model)
## # Effect Size for ANOVA
##
## Parameter | ε² | 95% CI
## ----------------------------------
## factor(gear) | 0.39 | [0.14, 1.00]
##
## - One-sided CIs: upper bound fixed at [1.00].And more…
Effect Size Conversion
The package also provides ways of converting between different effect sizes.
d_to_r(d = 0.2)
## [1] 0.0995
oddsratio_to_riskratio(2.6, p0 = 0.4)
## [1] 1.59And for recovering effect sizes from test statistics.
F_to_d(15, df = 1, df_error = 60)
## d | 95% CI
## -------------------
## 1.00 | [0.46, 1.53]
F_to_r(15, df = 1, df_error = 60)
## r | 95% CI
## -------------------
## 0.45 | [0.22, 0.61]
F_to_eta2(15, df = 1, df_error = 60)
## η² (partial) | 95% CI
## ---------------------------
## 0.20 | [0.07, 1.00]
##
## - One-sided CIs: upper bound fixed at [1.00].Effect Size Interpretation
The package allows for an automated interpretation of different indices.
interpret_r(r = 0.3)
## [1] "large"
## (Rules: funder2019)Different sets of “rules of thumb” are implemented (guidelines are detailed here) and can be easily changed.
interpret_cohens_d(d = 0.45, rules = "cohen1988")
## [1] "small"
## (Rules: cohen1988)
interpret_cohens_d(d = 0.45, rules = "gignac2016")
## [1] "moderate"
## (Rules: gignac2016)Citation
In order to cite this package, please use the following citation:
- Ben-Shachar M, Lüdecke D, Makowski D (2020). effectsize: Estimation of Effect Size Indices and Standardized Parameters. Journal of Open Source Software, 5(56), 2815. doi: 10.21105/joss.02815
Corresponding BibTeX entry:
@Article{,
title = {{e}ffectsize: Estimation of Effect Size Indices and Standardized Parameters},
author = {Mattan S. Ben-Shachar and Daniel Lüdecke and Dominique Makowski},
year = {2020},
journal = {Journal of Open Source Software},
volume = {5},
number = {56},
pages = {2815},
publisher = {The Open Journal},
doi = {10.21105/joss.02815},
url = {https://doi.org/10.21105/joss.02815}
}
Contributing and Support
If you have any questions regarding the the functionality of the package, you may either contact us via email or also file an issue. Anyone wishing to contribute to the package by adding functions, features, or in another way, please follow this guide and our code of conduct.