Volume 1 · 17 organizations · 90 slides
The Psychometrician’s Handbook
A plain-language reference for the psychometric methods behind clinical outcome assessment. Written, reviewed and argued over by researchers, clinicians and industry partners across 17 organizations.
Volume 1
90 slides, free as PDF and PowerPoint.
Volume 1
Correlations
Interactive
Play with the data
8 demos taken from the figures in Volume 1. Move the points and the sliders, and watch what happens to the correlation.
Four datasets, one correlation. r = 0.82 every time.
Drag a point. Watch the two coefficients disagree.
Narrow the sample, watch a strong correlation vanish.
At n = 25 the estimate swings. At n = 200 it settles.
Add noise to either measure, watch r pull toward zero.
One nested dataset, three different correlations.
Cut two measures into Likert categories and watch Pearson lose what polychoric keeps.
Push a distribution against its scale boundary.
With thanks to our contributors
A collaborative effort
32 people. 17 organizations. One handbook.
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Meaningful Change
Volume 2 takes on the question every trial eventually asks: how much change actually matters? Anchors, thresholds, responder definitions, and the evidence each one needs to stand up.
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