Table 1.
Demographic variables for DIF analyses and total VISA-A scores.
Fig 1.
Response frequency for item 3.
Negative skew for group 1 (symptoms ≤ 3 months).
Table 2.
Individual item fit, DIF for sex and symptom duration, and overall fit to the Rasch model.
Table 3.
Results of confirmatory factor analyses (CFA).
Table 4.
Multivariable regression analysis of differential item functioning (DIF) on the covariates sex, duration of symptoms, body mass index (BMI), and age group.