Body Appreciation Scale (BAS-2): Measurement Invariance across Genders and Item Response Theory Examination.

Background: The present study considers a measure of positive body image, the Body Appreciation Scale-2, which assesses acceptance and/or favourable opinions towards the body (BAS-2[29]). Differential functioning of the scale across the two genders, as well as its items, has not been excluded. The present study contributes to this area of knowledge via the employment of gender Measurement Invariance (MI) and Item Response Theory (IRT) analyses. Methods: : A group of 386 adults from the community were assessed (N = 394, 54.8% men, 43.1% women, M age = 27.48; SD = 5.57). Results: : MI analysis observed invariance across males and females at the configural level, and non-invariance at the metric level. Further, the two-parameter logistic model employed to observe IRT properties indicated that all items demonstrated, although variable, strong discrimination capacity. Conclusions: : The items showed increased reliability for latent levels of ∓ 2 SD from the mean level of Body Appreciation. The implications and interpretations of the findings for clinical practice are discussed.