Self-Other Differentiation Scale: Dimensionality, IRT Parameterization, and Measurement Invariance.

The Self-Other Differentiation Scale (Olver, Aries, & Batgos, 1989 ) is a self-report instrument assessing the experience of a separate sense of self from others. The authors aimed to examine its dimensionality, reliability, and measurement invariance across gender. It was completed by 348 participants (48% men) from 17 to 30 years old in Study 1, 348 participants (40% men) from 18 to 28 years old in Study 2, and 1,068 participants (49% men) from 17 to 28 years old in Study 3.