Rasch Analysis of the Korean Parenting Stress Index Short Form (K-PSI-SF) in Mothers of Children with Cerebral Palsy

The purpose of this study was to investigate the psychometric characteristics of the Korean Parenting Stress Index Short Form (K-PSI-SF) for mothers of children with cerebral palsy (CP) by using a Rasch analysis. The participants were 114 mothers of children with CP whose ages ranged from 2.79 to 11.90 years. The K-PSI-SF consists of 36 items, with a 5-point Likert scale grading along three subscales (Parent Distress, Parent–Child Dysfunctional Interaction, and Difficult Child). The response data were analyzed, and we determined the item fitness and item difficulty, rating scale fit, and separation index. The results show that two items did not have the required fitness. After these two items were deleted, the means of the 34 items in two of the subscales were statistically different from those of the original 36 items. Our analysis of the item difficulty identified the need to add easier question items. The 5-point Likert scale used in the questionnaire was found to be appropriate. This significance of this study is that it suggested the need to modify item fitness and difficulty level, as it identified the psychometric characteristics of the K-PSI-SF through a Rasch analysis based on the item response theory.