Vignettes
These vignettes show how to work with IRW data for common psychometric tasks.
R
Each of these vignettes uses the irw R package to fetch data and walks through a complete analysis.
R
How can I simulate item difficulties that reflect real-world distributions rather than idealized assumptions?
irw
R
What do discrimination parameters look like across many cognitive/educational datasets in the wild?
irw mirt ggplot2
R
How do I fit a multi-factor CFA model to an IRW personality dataset?
irw lavaan psych
R
Can simple linguistic features of item wording predict proportion correct across cognitive datasets?
irw ggplot2
R
What does Holland’s (1990) Dutch Identity reveal about the structure of IRT models — and does it hold in real data?
irw mirt imv ggplot2
R
How much does knowing how fast a person responded improve predictions of whether they answered correctly, over and above IRT ability estimates?
irw mirt imv splines
R
When do items in an RCT outcome measure respond differently to treatment, and what does ignoring this do to treatment-by-covariate interaction estimates?
irw lme4
Python
These vignettes use the irw Python package to fetch data.
Python
How do I fetch IRW data in Python and fit 1PL, 2PL, 3PL, and graded response models?
irw mirt girth