TAS-20 Item # | χ2(5) | pFDR | wABC | ESSD | Parametersa |
|---|
1 | 35.30 | < 0.001 | 0.089 | − 0.018 | a1, d1, d2 |
2 | 23.18 | < 0.001 | 0.164 | 0.157 | d2, d3 |
3 | 65.10 | < 0.001 | 0.433b | 0.670b | d2, d3, d4 |
9 | 26.03 | < 0.001 | 0.064 | − 0.021 | d1 |
11 | 30.47 | < 0.001 | 0.165 | 0.001 | a1, d2, d3 |
12 | 30.19 | < 0.001 | 0.149 | − 0.187 | d1 |
13 | 57.66 | < 0.001 | 0.064 | − 0.022 | a1, d1, d2, d3, d4 |
14 | 61.90 | < 0.001 | 0.031 | − 0.022 | a1, d1, d2, d3, d4 |
- Results indicate omnibus Wald tests of differential item functioning using the iterative anchor-selection method of Cao et al. (2017). P values (pFDR) are corrected for a 5% false discovery rate using the Benjamini–Hochberg procedure. Parameters that were significantly different between groups when tested alone with follow-up Wald tests (pFDR < 0.05) are indicated in the Parameters column. TAS-20 = 20-item Toronto Alexithymia Scale; wABC = weighted area between curves; ESSD = expected score standardized difference (in Cohen’s d metric); a1 = slope parameter; d1–d4 = item intercept parameters (i.e., item “difficulty” parameters)
- aParameters in bold are larger (i.e., more discriminating for a parameters and “easier” for d parameters) in the autistic group. Larger values of a indicate that the item is more strongly related to the latent trait in autistic adults, whereas larger values of d indicate that a given item response is endorsed at lower latent trait levels in autistic adults relative to the general population
- bPractically significant DIF (i.e., wABC > 0.3)
