Description
The Obsessive Compulsive Inventory-Revised (OCI-R) (Foa et al., 2002) is an 18-item self-report questionnaire and measures OCD symptoms across 6 subscales including washing, checking, neutralising, obsessing, ordering and hoarding. The scale is suitable for use with adults and adolescents (16 years +; Piqueras et al., 2009). Although initially developed for assessing OCD (when hoarding disorder was traditionally encapsulated under the OCD diagnosis), more recent research has established two scales to reliably assess both OCD and hoarding disorder (Wootton et al., 2015). The OCI-R can be used as a screening tool, an aid in diagnosis of both OCD and hoarding disorder, or as a tool to monitor progress in therapy. The OCI-R has the following subscales: Washing – assessing difficulty in touching objects that have been touched before and excessive washing due to feeling contaminated. Obsessing – assessing difficulty with thoughts including trying to control them, becoming upset by unpleasant thoughts, and a feeling of excessive unpleasant thoughts. Ordering – assessing challenges with ordering of objects. Checking – assessing excessive checking of items (doors, windows, drawers, taps, switches). Neutralising – assessing compulsions to count and excessive feelings towards numbers. Hoarding – assesses obtaining and keeping an excessive number of objects that are unneeded and that the client is finding it challenging to get rid of.

Validity and Reliability
The six-factor structure of the OCI-R has been demonstrated consistently across numerous clinical (Gönner et al., 2008; Huppert et al., 2007) and non-clinical samples (Chasson et al., 2013; Solem et al., 2010) and the OCI-R has shown adequate test-retest reliability (Foa et al., 2002; Chasson et al., 2013). It was found that the OCI-R can be separated into two measures for OCD and hoarding disorder that can differentiate between DSM-5 diagnostic groups (Wootton et al., 2015). The OCD component of the OCI-R correlates more strongly with a measure of anxiety (BAI, r =.61) than with measures of hoarding (SI-R r =.06; HRS r =-.01; Wootton et al., 2015). The hoarding disorder subscale of the OCI-R correlates strongly with the SI-R (r =.94) and HRS (r =.89) and only moderately with a measure of anxiety (BAI, r =.36; Wootton et al., 2015). Cronbach’s alphas for both parts of the OCI-R were high (r = .94 for hoarding disorder and r = .92 for OCD; Wootton et al., 2015). Receiver operating characteristic (ROC) analyses were conducted in order to ascertain the diagnostic sensitivity (percentage of patients who were accurately identified as having the diagnosis) and specificity (percentage of patients who were accurately identified as not having the diagnosis) of the hoarding disorder and OCD aspects of the ODI-R (Wootton et al., 2015). On the OCD scale a cut score of 12 provided the best balance between sensitivity and specificity, with a false positive rate of 17% and the false negative rate of 18%. The percentage of participants who were correctly classified based on a cut score of 12 was 83%. For the hoarding disorder scale a cutoff score of 6 provided the best balance between sensitivity and specificity. The false positive rate was 7% and the false negative rate was 9%. The percentage of participants who were correctly classified based on a cut score of 6 was 93%. A sample was used to calculate percentiles for the OCD and hoarding disorder components of the OCI-R. The total sample consisted of 474 adult (age 18 or older) participants (mean age = 47.40; SD = 14.23; 67% female). Of these, 201 had a primary diagnosis of hoarding disorder, 118 had a primary diagnosis of OCD, and 155 were a community sample without a psychiatric diagnosis (Wootton et al., 2015). The means (and SDs) are as follows: OCD scale (items 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18): Clinical (OCD diagnosis): mean = 23.94 (12.11) Normal (community sample): mean = 2.35 (3.54) Hoarding Disorder subscale (items 1, 7, 13): Clinical (hoarding disorder diagnosis): mean = 9.29 (2.45) Normal (community sample): mean = 1.32 (2.16) To calculate a clinical percentile for OCD subscales, a sample of 1,339 adults with a primary diagnosis of OCD was used (Abramovitch et al., 2020) and the means (and SDs) are as follows: Washing (items 5, 11, 17): mean = 4.62 (4.30) Obsessing (items 6, 12, 18): mean = 6.89 (3.76) Ordering (items 3, 9, 15): mean = 4.00 (3.68) Checking (items 2, 8, 14): mean = 4.09 (3.56) Neutralising (items 4, 10, 16): mean = 2.77 (3.49)

Interpretation
For the OCD component of the OCI-R (items 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18), the total score ranges from 0 – 60, with higher scores indicative of more severe OCD symptoms. A cutoff score of 12 is used to determine the likelihood of an OCD diagnosis (with a sensitivity of 82% and specificity of 83%). Normative and clinical percentiles are presented comparing the respondent’s scores to other adults (Wootton et al., 2015). A normative percentile rank of 50 indicates an average level of OCD symptoms in comparison to the the general population, and is indicative of typical (and healthy) levels of symptomatology. A clinical percentile rank of 50 indicates an average level of OCD symptoms in comparison to the clinical group (with an OCD diagnosis), and is indicative of elevated levels of symptomatology. For the hoarding disorder subscale of the OCI-R (items 1, 7, 13), the total score ranges from 0 – 12, with higher scores indicative of more severe hoarding symptoms. A cutoff score of 6 is used to determine the likelihood of a hoarding disorder diagnosis (with a sensitivity of 92% and specificity of 93%). A normative and clinical percentile are presented comparing the respondent’s scores to other adults (Wootton et al., 2015). A normative percentile rank of 50 indicates an average level of hoarding symptoms in comparison to the normative group, and is indicative of typical (and healthy) levels of symptomatology. A clinical percentile rank of 50 indicates an average level of OCD symptoms in comparison to the clinical group (with a hoarding disorder diagnosis), and is indicative of elevated levels of symptomatology. The OCD component of the OCI-R also reports the client’s score (between 0 – 12) across 6 subscales, with a clinical percentiles comparing the respondent’s scores to a comparison group whom have received a OCD diagnosis (Abramovitch et al., 2020): Washing (items 5, 11, 17) – assessing difficulty in touching objects that have been touched before and excessive washing due to feeling contaminated. Obsessing (items 6, 12, 18) – assessing difficulty with thoughts including trying to control them, becoming upset by unpleasant thoughts, and a feeling of excessive unpleasant thoughts. Ordering (items 3, 9, 15) – assessing challenges with ordering of objects. Checking (items 2, 8, 14) – assessing excessive checking of items (doors, windows, drawers, taps, switches). Neutralising (items 4, 10, 16) – assessing compulsions to count and excessive feelings towards numbers.

Developer
Foa, E. B., Huppert, J. D., Leiberg, S., Langner, R., Kichic, R., Hajcak, G., & Salkovskis, P. M. (2002). The Obsessive-Complusive Inventory: Development and validation of a short version. Psychological Assessment, 14(4), 485–495. https://doi.org/10.1037//1040-3590.14.4.485

Number Of Questions
18

References
Abramovitch, A., Abramowitz, J. S., Riemann, B. C., & McKay, D. (2020). Severity benchmarks and contemporary clinical norms for the Obsessive-Compulsive Inventory-Revised (OCI-R). Journal of Obsessive-Compulsive and Related Disorders, 27, 100557. https://doi.org/10.1016/j.jocrd.2020.100557 Chasson, G. S., Tang, S., Gray, B., Sun, H., & Wang, J. (2013). Further validation of a Chinese version of the Obsessive-Compulsive Inventory-Revised. Behavioural and cognitive psychotherapy, 41(2), 249–254. https://doi.org/10.1017/S1352465812000379 Gönner, S., Leonhart, R., & Ecker, W. (2008). The Obsessive-Compulsive Inventory-Revised (OCI-R): validation of the German version in a sample of patients with OCD, anxiety disorders, and depressive disorders. Journal of anxiety disorders, 22(4), 734–749. https://doi.org/10.1016/j.janxdis.2007.07.007 Huppert, J. D., Walther, M. R., Hajcak, G., Yadin, E., Foa, E. B., Simpson, H. B., & Liebowitz, M. R. (2007). The OCI-R: validation of the subscales in a clinical sample. Journal of anxiety disorders, 21(3), 394–406. https://doi.org/10.1016/j.janxdis.2006.05.006 Rodríguez, J. A. P., González, A. E. M., Montesinos, M. D. H., Rivas, M. Á. F., Mataix-Cols, D., & Alcázar, A. I. R. (2009). Psychometric properties of the Obsessive Compulsive Inventory-Revised in a non-clinical sample of late adolescents. Behavioral Psychology, 17(3), 561–572. https://www.researchgate.net/publication/229433233 Solem, S., Hjemdal, O., Vogel, P. A., & Stiles, T. C. (2010). A Norwegian version of the Obsessive-Compulsive Inventory-Revised: psychometric properties. Scandinavian journal of psychology, 51(6), 509–516. https://doi.org/10.1111/j.1467-9450.2009.00798.x Wootton, B. M., Diefenbach, G. J., Bragdon, L. B., Steketee, G., Frost, R. O., & Tolin, D. F. (2015). A contemporary psychometric evaluation of the Obsessive Compulsive Inventory-Revised (OCI-R). Psychological Assessment, 27(3), 874–882. https://doi.org/10.1037/pas0000075