[Updated] Statistical Power and Significance Testing Visualization
My Statistical Power and Significance Testing Visualization. By Kristoffer Magnusson now lets you vary effect size, sample size, power and significance level. There's also a new feature to rescale the...
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New d3.js visualization: Bayesian inference
Here's a new statistical visualization. This time I've tried to illustrate the logic of bayesian updating and hypothesis testing, using a Bayesian t-test. Check it out here: rpsychologist.com/d3/bayes/
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New d3.js visualization: Equivalence, non-inferiority and superiority testing
I recently published a new explorable visualization of equivalence, and non-inferiority testing. The visualization lets you explore the decision rules associated with these different hypotheses. It...
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Where Cohen went wrong – the proportion of overlap between two normal...
I've received many emails regarding the percent of overlap reported in my Cohen's d visualization. Observant readers, have noted that I report a different number than Cohen (and other authors). For...
View ArticleIntroducing 'powerlmm' an R package for power calculations for longitudinal...
Over the years I've produced quite a lot of code for power calculations and simulations of different longitudinal linear mixed models. Over the summer I bundled together these calculations for the...
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Are parallel simulations in the cloud worth it? Benchmarking my MBP vs my...
If you tend to do lots of large Monte Carlo simulations, you've probably already discovered the benefits of multi-core CPUs and parallel computation. A simulation that takes 4 weeks without...
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Confounded dose-response effects of treatment adherence: fitting Bayesian...
Something that never ceases to amaze (depress) me, is how extremely common it is to see casual claims in RCTs, that are not part of the randomization. For instance, the relationship between treatment...
View ArticlePower analysis for longitudinal multilevel models: powerlmm 0.2.0 is now out...
My R packge powerlmm 0.2.0 is now out on CRAN. It can be installed from CRAN https://cran.r-project.org/package=powerlmm or GitHub https://github.com/rpsychologist/powerlmm.Changes in version 0.2.0New...
View ArticleSlides from my talk on how to do power analysis for longitudinal 2- and...
Here's the slides from a talk I gave recently at Stockholm University: "Power Analysis for Longitudinal 2- and 3-Level Models: Challenges and Some Solutions Using the R Package powerlmm".The slides...
View ArticlePower analysis for longitudinal multilevel models: powerlmm 0.3.0 is now out...
My R package powerlmm 0.3.0 is now out on CRAN. It can be installed from CRAN https://cran.r-project.org/package=powerlmm or GitHub https://github.com/rpsychologist/powerlmm.New featuresThis version...
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Do you really need a multilevel model? A preview of powerlmm 0.4.0
In this post I will show some of the new simulation features that will be available in powerlmm 0.4.0. You can already install the dev version from GitHub.# GitHub...
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Estimating treatment effects and ICCs from (G)LMMs on the observed scale...
.smaller-table { font-size:12px; }When a multilevel model includes either a non-linear transformation (such as the log-transformation) of the response variable, or of the expectations via a GLM...
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New paper: The consequences of ignoring therapist effects in longitudinal...
We just published a new paper where we show that trials on psychological interventions continue to ignore the possibility of therapist effects, and show what factors influence the consequences of...
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Change over time is not "treatment response"
This will be a non-technical post illustrating the problems with identifying treatment responders or non-responders using inappropriate within-group analyses. Specifically, I will show why it is...
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Mediation, confounding, and measurement error
Mediation might be the ultimate example of how a method continues to be used despite a vast number of papers and textbooks describing the extremely strong assumptions required to estimate unbiased...
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Heterogeneous treatment effects and homogeneous outcome variances
Recently there has been a couple of meta-analyses investigating heterogeneous treatment effects by analyzing the ratio of the outcome variances in the treatment and control group. The argument made in...
View ArticleConfounded dose-response effects of treatment adherence: fitting Bayesian...
Something that never ceases to amaze (depress) me, is how extremely common it is to see causal claims in RCTs, that are not part of the…
View ArticlePower analysis for longitudinal multilevel models: powerlmm 0.2.0 is now out...
My R packge powerlmm 0.2.0 is now out on CRAN. It can be installed from CRAN https://cran.r-project.org/package=powerlmm or GitHub…
View ArticleSlides from my talk on how to do power analysis for longitudinal 2- and...
Here's the slides from a talk I gave recently at Stockholm University: "Power Analysis for Longitudinal 2- and 3-Level Models: Challenges…
View ArticlePower analysis for longitudinal multilevel models: powerlmm 0.3.0 is now out...
My R package powerlmm 0.3.0 is now out on CRAN. It can be installed from CRAN https://cran.r-project.org/package=powerlmm or GitHub…
View Article