The Order-Processing Questionnaire (OPQ) is a brief parental-report measure designed to assess children’s everyday ordering skills, which have been linked to early mathematical development. This study aimed to validate the OPQ’s two-factor structure, previously identified by O’Connor et al. (2018), using confirmatory factor analysis (CFA) in a larger sample. Parents of 509 children in their first year of primary school in Northern Ireland completed the OPQ online. CFA tested the original two-factor model comprising positively and negatively worded items. Model fit was mixed: while indices such as the Comparative Fit Index (CFI) and Standardised Root Mean Square Residual (SRMR) indicated adequate fit (i.e. the analysis provides a reasonable representation of the patterns in the data), the Root Mean Square Error of Approximation (RMSEA) and chi-square test suggested poorer fit (i.e. analysis does not capture those patterns in the data well). Factor loadings were moderate to strong, and internal consistency was acceptable for the Positive Item factor but weaker for the Negative Item factor, likely reflecting the smaller number of negatively worded items. Evidence of discriminant validity was observed, although convergent validity was stronger for the Positive Item factor. These findings provide partial support for the OPQ’s two-factor structure but highlight the need for refinement, particularly regarding negatively phrased items. The study underscores the OPQ’s potential as a non-invasive tool for identifying children at risk of early mathematical difficulties while recommending further work to improve its psychometric properties and examine predictive validity. Incorporating socioeconomic status measures and multi-informant reports in future studies will strengthen the OPQ’s utility as a screening instrument to support early identification and intervention in educational settings.
O'Connor et al. (Wed,) studied this question.