Assessing Child Pain-Related Injustice Appraisals: A Discriminant Content Analysis Study

Child pain-related injustice appraisals, associated with adverse pain-related functioning, are commonly assessed using the Injustice Experience Questionnaire (IEQ). However, the IEQ was initially developed for adults. Recent qualitative phenomenological work highlighted pain-related injustice themes among children that are seemingly not captured by the IEQ. Furthermore, research in adults and children has shown strong associations between the IEQ and both pain catastrophising and disability. These issues raise concerns regarding the content validity and discriminant content validity of the IEQ for paediatric populations. This study assessed the content validity and discriminant content validity of the IEQ items and a set of novel items generated through previous qualitative work.

Content and discriminant content validity of the items was assessed by 96 adult judges rating items as measuring child injustice appraisals, as well as measuring competing constructs: pain catastrophising, disability and negative affect. Wilcoxon signed-rank tests were applied to assess content and discriminant content validity.

Four of 12 IEQ items displayed content validity as well as discriminant content validity against pain catastrophising and disability. Eight of 13 newly generated items displayed content validity as well as discriminant content validity against pain catastrophising and disability. Only two of all 25 items displayed discriminant content validity against negative affect.

This study revealed the IEQ to lack discriminant content validity for use in a paediatric context. An item pool was created to assess child pain-related injustice appraisals, displaying both content validity and discriminant content validity against the competing constructs of pain catastrophising and disability.

The current study both reveals issues in applying the IEQ to assess child pain-related injustice appraisals and advances research on child pain-related injustice appraisals by providing an item pool displaying both content validity and discriminant content validity against the competing constructs of child pain catastrophising and child disability.