Development of the scrupulosity inventory: A factor analysis and construct validity study

Background and objectives

Scrupulosity, despite its considerable prevalence and morbidity, remains under-investigated. The present study develops and examines the psychometric properties of a comprehensive assessment tool, the Scrupulosity Inventory (SI).

Methods

The SI, along with other measures of obsessive-compulsive disorder (OCD) and perfectionism, were administered to a sample (N = 150) of college undergraduates similar in size to other scale development studies of related measures. We conducted exploratory and confirmatory factor analyses of the SI, examined its convergent and divergent validity, and assessed its ability to predict categorical diagnoses of scrupulosity using a receiver operator characteristic analysis.

Results

We found a well-fitting confirmatory bifactor model (RMSEA = 0.049) with a strong general Scrupulosity factor (${\omega }_{H_S}=0.907$) and specific factors for Personal Violations (${\omega }_{H_S}=0.212$), Ritualized Behavior (${\omega }_{H_S}=0.505$), Interference with Life (${\omega }_{H_S}=0.254$), and Problem Pervasiveness (${\omega }_{H_S}=0.430$). As predicted, we also found the strongest convergence (r = 0.63) between the SI and the Penn Inventory of Scrupulosity (PIOS), intermediate convergence (r = 0.54) between the SI and Perfectionism Inventory (PI), and weaker convergence (r = 0.47) between the SI and YBOCS. Finally, we found that a categorical diagnosis of scrupulosity was highly predicted by the SI (AUC = 0.84), less well-predicted by the PIOS (AUC = 0.75) and less well predicted by the YBOCS (AUC = 0.69).

Limitations

This study was conducted among a sample of undergraduates at a religiously affiliated university.

Conclusions

These results suggest utility in using the SI to measure the severity of scrupulosity symptoms and that scrupulosity and OCD may present significantly different clinical features.