Characteristics | Parameter | Values |
---|---|---|
PRO instrument | Number of items J | 4, 7, 10 |
Number of response categories M (response options from 0 to M-1) | 3, 5 | |
Item locations (δj) and category thresholds (δjl) distribution | First archetype: \({\delta}_j=-0.25+\frac{0.5}{J-1}\left(j-1\right),\kern0.5em j=1\dots J\) (Regularly spaced between − 0.25 + 0.25) δjl defined as the percentiles from a normal distribution with SD of 2.5 Second archetype: \({\delta}_j=-1+\frac{2}{J-1}\left(j-1\right),\kern0.5em j=1\dots J\) (Regularly spaced between −1 + 1), δjl defined as the percentiles from a normal distribution with SD of 1.5 | |
Calibration sample | Sample size Nvalidation | 100, 250, 500 |
Variance | 1, 2 | |
Mean of latent trait | 0 | |
Trial sample | Sample size Ntrial | 50, 100, 200, 500 (per group) |
Effect size (Standardized mean difference between groups) γ | 0, 0.2, 0.5 | |
Mean of latent trait μ | 0, 0.5, 2 | |
Variance within each group | 1 |