Mokken scales for testing both pre- and postintervention: an analysis of the Clinical Outcomes in Routine Evaluation-Outcome Measure (CORE-OM) before and after counseling.

Mokken scaling is increasingly being applied to assessing the extent to which clinical scales possess clinically useful properties, especially invariant item ordering (IIO). These scales are often used to track progress in symptoms over time to evaluate the success of an intervention. Such interventions are designed to affect psychopathological trait levels overall but may in some cases act disproportionately on some symptoms over others.