Table 6 PHQ9 – Rating Scale Model Error rates by sample size (collapsing across items)
From: Rasch fit statistics and sample size considerations for polytomous data
Infit t | Infit t | Infit MNSQ | Infit MNSQ | Infit MNSQ | Outfit t | Outfit t | Outfit MNSQ | Outfit MNSQ | Outfit MNSQ | |
|---|---|---|---|---|---|---|---|---|---|---|
Sample | < -2 | > 2 | < 0.7 | > 1.2 | > 1.3 | < -2 | > 2 | < 0.7 | > 1.2 | > 1.3 |
25 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 0 | 2 |
50 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 |
100 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 0 | 1 |
200 | 1 | 1 | 0 | 0 | 2 | 1 | 0 | 0 | 0 | 0 |
400 | 1 | 3 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 |
800 | 2 | 3 | 1 | 0 | 1 | 1 | 2 | 2 | 0 | 0 |
1600 | 2 | 5 | 0 | 0 | 1 | 2 | 2 | 0 | 0 | 0 |
3200 | 2 | 5 | 0 | 0 | 1 | 4 | 2 | 0 | 0 | 0 |