The VOCI was designed to provide a self-report assessment of a range of obsessions, compulsions, avoidance behaviour, and personality characteristics of known or theoretical importance in obsessive–compulsive disorder (OCD).
The Vancouver Obsessional Compulsive Inventory (VOCI) is a 55-item adult self-report questionnaire designed to provide a comprehensive assessment of obsessions, compulsions, avoidance behaviour, and personality characteristics of importance in obsessive-compulsive disorder (OCD) (Thordarson et al., 2004). Respondents rate how applicable each symptom statement is to them, providing symptom endorsement and overall OCD symptom severity. The VOCI was primarily developed as a revision of the Maudsley Obsessional-Compulsive Inventory (MOCI), with design changes informed by limitations identified in OCD self-report measures, including clearer item wording, a more flexible response format, and broader symptom coverage (Hodgson & Rachman, 1977).
Unlike brief screening measures, the VOCI provides dimensional assessment across six OCD symptom domains, making it particularly useful for understanding a client’s OCD symptom profile. The VOCI is not intended for diagnosis, and diagnostic decisions should be based on comprehensive clinical assessment.
The VOCI assesses OCD symptoms through six subscales:
The VOCI can be used in a range of clinical contexts to support assessment and ongoing care for individuals with OCD, including:
It should be noted that the VOCI was developed in 2004, prior to the current DSM-5 (2013) classification of Hoarding Disorder as a diagnosis distinct from OCD. The VOCI Hoarding subscale was designed to assess hoarding as an obsessive-compulsive symptom dimension, rather than an independent disorder with separate diagnostic criteria. Current evidence does not support the use of the VOCI as a standalone measure for assessing Hoarding Disorder. Other scales, such as the OCI-R’s Hoarding subscale has received more validation in that context. Elevated Hoarding subscale scores should prompt clinical consideration of whether hoarding symptoms are better understood as OCD-related hoarding (typically ego-dystonic and driven by intrusive thoughts) or more consistent with Hoarding Disorder (often ego-syntonic and driven by emotional attachment). Beyond the Hoarding subscale, the VOCI’s remaining symptom dimensions continue to map onto the core OCD symptom dimensions that have been consistently replicated in factor-analytic research and remain central to DSM-5-TR conceptualisation of OCD. The reclassification of OCD from Anxiety Disorders into its own diagnostic category did not substantively alter the definition of obsessions and compulsions themselves.
The VOCI total score ranges from 0 to 220, where respondents rate how true each item is of them, with higher scores representing greater overall current OCD symptom severity. The total score should be interpreted alongside subscale scores to understand symptom heterogeneity.
The 55 items are organized into six symptom subscales, each representing a distinct OCD-related domain with its own item composition and score range.
For clinical interpretation, NovoPsych includes percentile ranks drawn from Thordarson et al. (2004) for the total and subscale scores relative to:
A percentile near 50 indicates a score typical of the reference group, while higher percentiles indicate greater obsessive–compulsive symptom levels relative to that group.
To make scores easier to interpret, NovoPsych groups non-clinical percentile scores into three descriptive ranges to aid with the interpretation of both the total score and all subscales:
On first administration, results are displayed as a horizontal bar graph of the total score compared to both OCD and non-clinical norms, allowing visual comparison of symptom severity across reference populations.
A second horizontal bar graph is shown for the subscale comparisons. An example for the Contamination subscale:
If administered more than once, longitudinal line graphs are presented for the total score and each subscale, tracking the trajectory of symptoms over time (subscale graph examples of Contamination and Checking shown below).
A meaningful change in obsessive-compulsive symptoms is defined as a change of 19 or more points in the total score, based on the Minimally Important Difference (MID) calculation.
The VOCI demonstrates strong known-groups validity, in other words it effectively distinguishes individuals with OCD from both clinical and non-clinical comparison groups. In validation studies, individuals with OCD (n = 88) scored significantly higher than anxiety/depression controls (n = 60), community adults (n = 39), and students (n = 200) on the VOCI total, Contamination, Checking, Just Right, and Indecisiveness subscales. For Obsessions and Hoarding subscales, the OCD group scored significantly higher than non-clinical controls but not the anxiety/depression group, reflecting the transdiagnostic nature of these symptoms. The VOCI also discriminates between OCD subtypes: individuals classified as Cleaners, Checkers, Obsessionals, Orderers, or Hoarders based on Y-BOCS interviews scored significantly higher on their corresponding VOCI subscales (Thordarson et al., 2004).
The VOCI total score correlates highly with other self-report OCD measures: Padua Inventory (r = 0.87 in OCD sample; r = 0.79 in students), MOCI (r = 0.78 in OCD; r = 0.64 in students), and self-report Y-BOCS (r = 0.68 in OCD), indicating that it measures core OCD symptom severity. These correlations were significantly higher than correlations with the Beck Depression Inventory (BDI) (r = 0.54 in OCD), supporting convergent and discriminant validity. Subscale-level analyses show strong correlations between corresponding subscales (e.g., VOCI Contamination with Padua Contamination, r = 0.85) and weaker correlations with non-corresponding measures (Thordarson et al., 2004). For clinicians, this means the VOCI can be used with confidence that elevated scores reflect OCD-specific symptomatology rather than general distress, and that subscale scores meaningfully map onto recognised symptom dimensions.
In an OCD sample (n = 28, mean interval = 47 days), test-retest reliability coefficients were excellent for the VOCI total score (r = 0.96) and all subscales (r = 0.90–0.97), indicating high stability of scores in clinical populations. In a student sample, test-retest reliability was more modest(r = 0.50–0.62), likely due to floor effects and range restriction in low-symptom populations rather than true measurement instability (Thordarson et al., 2004). This level of stability supports the use of the VOCI for tracking OCD symptom patterns over time in clinical populations.
The VOCI demonstrates excellent internal consistency across populations (Thordarson et al., 2004). A t-test analysis was also undertaken to see if the scale could discriminate between different subtypes of OCD. The results clearly support the known-groups validity of the Contamination, Checking, Obsessions, and Hoarding subscales. Test re-test reliability among OCD groups is high, with all coefficients 0.9 or above after 47 days. For the student sample, however, test retest reliability was poor (0.5 to 0.6).
Scores range from .90–.98, indicating that items reliably measure a cohesive construct. Subscale internal consistency is generally good to excellent in clinical samples (α = .85 – .96), with slightly lower but still acceptable values in the smaller community adult sample (α = .70 – .81). These findings indicate that the VOCI and its subscales produce reliable, internally consistent scores.
The VOCI was developed through systematic revision of the MOCI-R, using factor-analytic and item-analytic strategies with an OCD sample (n = 88). Factor analysis yielded a six-factor solution with excellent simple structure. The six-factor structure has been replicated in non-clinical samples (Chiorri et al., 2011) and confirmed in a large German OCD sample (Gönner et al., 2010). The factors are relatively independent, with inter-factor correlations ranging from 0.06 to 0.33. Taken together, these findings support the use of the VOCI subscales to understand and monitor different OCD symptom areas.
Normative data for the VOCI are derived from Thordarson et al.’s (2004) original validation study conducted in Canada. The study included four comparison groups:
For clinical interpretation, NovoPsych created a pooled non-clinical sample by combining the community adults and student groups (total n = 239; M = 32.30, SD = 24.74), using the formula for calculating a weighted mean and pooled standard deviation. This combination decision was made because the community adults sample alone was too small for reliable percentile estimation. While the two groups differ in mean age (community adults M = 41.0 years; students M = 19.9 years), research indicates weak associations between VOCI scores and demographic variables, including age (Chiorri et al., 2011), supporting the appropriateness of combining these samples. The anxiety/depression control group was not included in the non-clinical reference, as it represents a clinical population and was included in the original study to evaluate discriminant validity rather than to serve as a normative comparison group.
For interpretation, raw VOCI scores are first converted to percentiles based on the non-clinical reference distribution (Table 1). Severity descriptors are anchored to the non-clinical sample, as this reference identifies when symptoms exceed typical levels, the key question for clinical interpretation. The OCD percentile is provided separately to contextualise severity relative to individuals with diagnosed OCD. Percentile-anchored descriptors have been created by NovoPsych to assist in score interpretation. These descriptors are based on the non-clinical reference sample and divide scores into three equal ranges (lower, middle, and upper thirds), providing descriptive thresholds to aid in interpretation, rather than clinical cutoffs.
Higher percentiles indicate greater obsessive-compulsive symptom severity relative to individuals without OCD. For example, a score at the 80th percentile indicates symptom levels higher than80% of the non-clinical reference group and may warrant clinical attention (but does not indicate diagnosis)
The same tri-band system applies to both the VOCI total score and all subscales, facilitating consistent interpretation across scales.
The VOCI is not a diagnostic tool. It measures the severity and patterns of obsessive-compulsive symptoms across six dimensions, but it does not have validated clinical cut-off scores that distinguish between individuals with and without OCD. Diagnostic decisions should always be based on comprehensive clinical assessment, including structured diagnostic interviews such as the SCID or MINI. The VOCI is best understood as a dimensional measure of symptom endorsement and severity that can support clinical judgement.
The VOCI was developed in 2004, before the DSM-5 (2013) reclassified Hoarding Disorder as a condition distinct from OCD. The VOCI Hoarding subscale was designed to assess hoarding as an obsessive-compulsive symptom dimension, not as an independent disorder with its own diagnostic criteria. Current evidence does not support the use of the VOCI as a standalone measure for assessing Hoarding Disorder. Elevated Hoarding subscale scores should prompt clinical consideration of whether hoarding symptoms are better understood as OCD-related hoarding (typically ego-dystonic and driven by intrusive thoughts) or more consistent with Hoarding Disorder (often ego-syntonic and driven by emotional attachment). Other scales, such as the Saving Inventory–Revised (SI-R) or the OCI-R‘s Hoarding subscale, have received more validation for assessing Hoarding Disorder specifically.
VOCI’s six subscales provide a detailed picture of which OCD symptom domains are most prominent for a given client, which can directly inform case formulation and guide treatment focus. For example, elevated Contamination scores may suggest a focus on exposure to contamination triggers and response prevention of washing or cleaning rituals, while elevated Obsessions scores, capturing intrusive thoughts related to harm, sexuality, or morality, may indicate a need for cognitive interventions that target the personal significance and misinterpretation of intrusive thoughts, alongside imaginal or in vivo exposure. Elevated Just Right scores may point towards symmetry-related exposures and reduction of ordering, arranging, or repeating behaviours. By identifying the most endorsed symptom areas and specific items, clinicians can prioritise treatment targets and tailor exposure hierarchies to the client’s individual presentation.
The VOCI was developed as a revision of the original Maudsley Obsessional-Compulsive Inventory (MOCI), one of the most widely used OCD self-report measures. The VOCI improved upon the MOCI by introducing a five-point Likert response format (enhancing sensitivity to change), including broader symptom coverage across both cognitive and behavioural dimensions of OCD, and incorporating subscales for obsessions, hoarding, indecisiveness, and ‘just right’ experiences that were not well captured by earlier instruments. Compared to the Obsessive-Compulsive Inventory–Revised (OCI-R), the VOCI offers more items per subscale, providing more content coverage of each symptom domain.
Indecisiveness – characterised by difficulty making decisions, perfectionistic doubt, and intolerance of uncertainty – has long been recognised as a personality characteristic of theoretical importance in OCD. The inclusion of this subscale reflects the VOCI’s original design intent to assess not only observable compulsions and intrusive thoughts, but also personality features associated with obsessive-compulsive presentations. While indecisiveness is not unique to OCD and can be present across a range of conditions, elevated scores on this subscale can provide clinically useful information about the client’s relationship with uncertainty and doubt, which may be relevant to both case formulation and therapeutic strategies such as tolerance of uncertainty training.
Thordarson, D. S., Radomsky, A. S., Rachman, S., Shafran, R., Sawchuk, C. N., & Hakstian, A. R. (2004). The Vancouver Obsessional Compulsive Inventory (VOCI). Behaviour Research and Therapy, 42(11), 1289–1314. https://doi.org/10.1016/j.brat.2003.08.007
Chiorri, C., Melli, G., & Smurra, R. (2011). Second-order factor structure of the Vancouver Obsessive Compulsive Inventory (VOCI) in a non-clinical sample. Behavioural and Cognitive Psychotherapy, 39(5), 561–577. https://doi.org/10.1017/S1352465810000913
Gönner, S., Ecker, W., Leonhart, R., & Limbacher, K. (2010). Multidimensional assessment of OCD: integration and revision of the Vancouver Obsessional-Compulsive Inventory and the Symmetry Ordering and Arranging Questionnaire. Journal of Clinical Psychology, 66(7), 739–757. https://doi.org/10.1002/jclp.20690
Radomsky, A. S., Ouimet, A. J., Ashbaugh, A. R., Lavoie, S. L., Parrish, C. L., & O’Connor, K. P. (2006). Psychometric properties of the French and English versions of the Vancouver Obsessional-Compulsive Inventory and the Symmetry Ordering and Arranging Questionnaire. Cognitive Behaviour Therapy, 35(3), 164–173. https://doi.org/10.1080/16506070600827198
Thordarson, D. S., Radomsky, A. S., Rachman, S., Shafran, R., Sawchuk, C. N., & Ralph Hakstian, A. (2004). The Vancouver Obsessional Compulsive Inventory (VOCI). Behaviour Research and Therapy, 42(11), 1289–1314. https://doi.org/10.1016/j.brat.2003.08.007
Hodgson, R. J., & Rachman, S. (1977). Obsessional-compulsive complaints. Behaviour Research and Therapy, 15(5), 389–395. https://doi.org/10.1016/0005-7967(77)90042-0
