Overview
The IUSC assesses children’s tendency to react negatively on an emotional, cognitive, and behavioural level to uncertain situations and events. The measure includes parallel child- and parent-report forms adapted from the 27-item English version of the adult IUS (Buhr & Dugas, 2002; Freeston et al., 1994). The IUSC items were reworded to enhance child compatibility. A short-form version includes 12-Items (Cornacchio et al., 2018).Scoring & Interpretation
Respondents rate the extent to which they agree with each item along a 5-point scale (1=not at all, 3= somewhat, 5= very much), resulting in total scores ranging from 27 to 135. For the IUSC- child-report instructions read: “How well do these statements describe you?”For the parent-report the instructions read ' “You will find below a series of statements which describe how children may react to uncertainty. Please use the scale below to describe to what extent each item is characteristic of your child.”Psychometric Properties
Internal Consistency
Across the full sample, internal consistency was excellent for the IUSC parent-report form (α =.96 and child-report form (α =.92). Internal consistency was excellent within the community sample (parent-report α =.94, child-report α =. 91) and clinical sample (parent-report α =.96, child- report α =.94).
Test-Retest Reliability
None reported in original paper - see Osmanagaogiu et al., (2018) & Zemestani et al., (2022)
Factor Structure
None reported in the original paper (Comer et al., 2007) Subsequent research reports inconsistent findings in regard to the structure of the IUSC. With some supporting a two-factor structure (prospective IU: apprehensive anxiety/fear regarding future events and Inhibitory IU: present-focused inhibition of behaviour due to uncertainty and negative reactions to the presence of uncertainty) and others a one factor/bifactor structure (e.g., Cornacchio et al. 2018; Osmanagaoglu et al., 2021; Zemestani et al., 2022).
Validity
Convergent validity: The child-report form of the IUSC evidenced large associations with children’s self-reports of anxiety (Multidimensional Anxiety Scale for Children: MASC) and worry (Penn-State Worry Questionnaire for Children (PSWQ-C), and a moderate to large association with children’s self-reports of reassurance-seeking behavior (Reassurance-Seeking Scale for Children: RSSC). Convergent validity of the child-report form was also stable across young and old cohorts within the sample. In contrast, although acceptable convergent validity was demonstrated with respect to the parent-report form across the full sample, among older (16–17 years) and younger children (7–8 years) the parent-report form evidenced weak convergent validity.
Measurement Invariance
Known-groups validity: (ANOVA) Significantly higher scores were found among the clinical sample (anxiety disorder) compared to the community sample on both the IUSC parent-report (p <.0001, d = 1.01) and child- report (p <.005, d =.61).