Padua Inventory – Washington State University Revision (PI-WSUR)

Abstract

The Padua Inventory – Washington State University Revision (PI-WSUR) is a sophisticated, 39-item psychological scale developed to provide a precise, dimensional assessment of the severity and specific symptom clusters associated with Obsessive Compulsive Disorder (OCD). Developed by Burns and colleagues, the PI-WSUR emerged from a rigorous revision of the original Padua Inventory, aiming specifically to enhance the differentiation among cognitive components (such as worry and obsessions) and behavioral components (compulsions).

The instrument utilizes a robust five-factor structure, which maps onto the core phenomenological domains of OCD, including contamination, checking, and intrusive thoughts of harm. By requiring respondents to rate the degree of disturbance caused by specific thoughts and behaviors on a five-point scale, the PI-WSUR delivers a nuanced measure of both symptom severity and associated functional impairment, proving invaluable for clinical research and tailored treatment planning.

Keywords

Obsessive Compulsive Disorder, PI-WSUR, Contamination, Checking, Obsessions, Compulsions, Psychological assessment, Symptom dimensions, Washington State University Revision, Intrusive thoughts, Dimensional assessment, Symptom severity, Behavioral research, Clinical psychology

Authors

G. Leonard Burns, S. Keortge, G. Formea, L.G. Sternberger

Purpose

The primary objective of developing the PI-WSUR was to create a psychometrically superior and detailed measure capable of capturing the diverse and complex symptomology inherent in Obsessive Compulsive Disorder. Earlier assessment tools often failed to clearly separate cognitive distress (e.g., obsessional thoughts and excessive worry) from overt behavioral rituals (e.g., compulsions), leading to diagnostic ambiguity.

By successfully establishing five distinct subscales, the PI-WSUR enables clinicians and researchers to generate a precise profile of an individual’s specific OCD symptom pattern. This dimensional approach is crucial for differential diagnosis, facilitating the selection and customization of evidence-based interventions, particularly cognitive behavioral therapies (CBT).

Construct

The PI-WSUR is constructed to measure the frequency and severity across five primary symptom dimensions of OCD, which are conceptualized as distinct yet correlated psychological constructs. A central feature of the revision is the explicit distinction drawn between obsessions (recurrent, involuntary, and intrusive thoughts) and compulsions (repetitive behaviors or mental acts performed to reduce anxiety).

This multi-faceted, dimensional approach acknowledges the heterogeneity of OCD, moving beyond reliance on a single total score to provide a comprehensive analysis of the disorder. The specific constructs assessed include contamination fears and subsequent washing rituals, various forms of checking behaviors, ordering and grooming compulsions, and purely cognitive or impulsive obsessions related to potential harm to self or others.

Validity

The validity of the PI-WSUR is strongly supported by its empirically derived and clinically meaningful factor structure, which confirms robust construct validity by aligning closely with established clinical dimensions of OCD phenomenology. A key goal of the Washington State University Revision was to improve discriminant validity.

Research establishing the scale’s psychometric properties confirms that the subscales effectively differentiate between unique symptom clusters—for instance, distinguishing contamination fears from repetitive checking rituals. Furthermore, the scale demonstrates strong criterion-related validity, showing expected correlations with other established measures of OCD severity while simultaneously capturing unique variance attributable to its specific dimensional factors.

Reliability

The PI-WSUR exhibits good internal consistency across all five of its subscales. This statistical reliability suggests that the items grouped within each factor consistently and reliably measure the same underlying construct.

The careful and rigorous revision process undertaken by Burns and colleagues ensured that the final 39 items maintain high reliability coefficients. This makes the PI-WSUR a dependable and stable tool suitable for use in both clinical diagnostic settings and longitudinal research trials involving repeated measures of symptom change.

Factor Analysis

The development and refinement of the PI-WSUR were guided by detailed factor analysis, which was essential for identifying the underlying structure of OCD symptoms. This analysis led to the adoption of a stable five-factor model for grouping the 39 items, representing a significant psychometric advancement over the original, less differentiated Padua Inventory.

The resulting five factors, which allow for a significantly more precise diagnostic and symptom profile, are categorized as follows:

• Contamination obsessions and washing compulsions (Items 1–10)
• Dressing/grooming compulsions (Items 11–13)
• Checking compulsions (Items 14–23)
• Obsessional thoughts of harm to self/others (Items 24–30)
• Obsessional impulses to harm self/others (Items 31–39)

Instrument

Test Type: Self-report questionnaire/Psychological scale

Format: 39 items rated on a 5-point Likert scale (ranging from 0 to 4)

Language Available: English (Original), with translations likely available for research purposes.

Population Group: Clinical and non-clinical populations

Age Group: Adolescents and Adults

Population Details: Primarily utilized in research and clinical settings focusing on individuals presenting with symptoms of Obsessive Compulsive Disorder.

Test Methodology: Respondents are instructed to choose the reply that most accurately reflects the degree of disturbance the specific thought or behavior creates in their lives, using the following ordinal scale:

1. Not at all
2. A little
3. Quite a lot
4. A lot
5. Very much

Keywords

Obsessive Compulsive Disorder, PI-WSUR, Dimensional assessment, Symptom severity, Behavioral research, Contamination fears, Impulse control, Clinical psychology, Psychometrics, Self-report measure

Authors

Author ORCID Identifier: Not specified in source content.

Affiliation Email addresses: Not specified in source content.

Correspondence Address: G. Leonard Burns, Department of Psychology, Washington State University, Pullman, WA 99164-4820

Permissions & Fee and Test Year

The Padua Inventory – Washington State University Revision was initially released in 1995, with the definitive detailed psychometric analysis published in 1996. The scale is widely accessible and frequently employed in academic research globally.

For specific inquiries regarding permissions for commercial use or any associated fees, interested parties should direct correspondence to the primary author, G. Leonard Burns, at his affiliation address at Washington State University.

Reference’s

The primary psychometric validation and detailed description of the revision are established in the following foundational academic publications:

• Burns, G.L. (1995). Padua Inventory-Washington State University Revision. Pullman, WA: Author. (Available from G. Leonard Burns, Department of Psychology, Washington State University, Pullman, WA 99164-4820)
• Burns, G.L., Keortge, S., Formea, G., & Sternberger, L.G. (1996). Revision of the Padua Inventory of obsessive compulsive disorder symptoms: Distinctions between worry, obsessions, and compulsions. Behavior Research and Therapy, 34, 163-173.

Additional supporting documentation and related research are available through the following academic links:

• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3395932/
• http://www.sid.ir/fa/VEWSSID/J_pdf/68113894501.pdf

The original PDF of the PI-WSUR instrument can be downloaded here: http://www.psychologie.tu-dresden.de/i2/klinische/mitarbeiter/materialien/pd-wsur.pdf.

Another related academic PDF is available here: http://ses.library.usyd.edu.au/bitstream/2123/4026/1/j-swinbourne-thesis.pdf.

Items of the Padua Inventory – Washington State University Revision (PI-WSUR)

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

The following statements refer to thoughts and behaviors which may occur to everyone in everyday life. For each statement, choose the reply which best seems to fit you and the degree of disturbance which such thoughts or behaviors may create. Rate your replies as follows:

0= Not at all, 1= A little, 2= Quite a lot, 3= A lot, 4=Very much

1. I feel my hands are dirty when I touch money
2. I think even slight contact with bodily secretions (perspiration, saliva, urine, etc.) may contaminate my clothes or somehow harm me
3. I find it difficult to touch an object when I know it has been touched by strangers or by certain people
4. I find it difficult to touch garbage or dirty things
5. I avoid using public toilets because I am afraid of disease and contamination
6. I avoid using public telephones because I am afraid of contagion and disease
7. I wash my hands more often and longer than necessary
8. I sometimes have to wash or clean myself simply because I think I may be dirty or ‘contaminated’
9. If I touch something I think is ‘contaminated’ I immediately have to wash or clean myself
10. If an animal touches me I feel dirty and immediately have to wash myself or change my clothing.
11. I feel obliged to follow a particular order in dressing, undressing and washing myself
12. Before going to sleep I have to do certain things in a certain order
13. Before going to bed I have to hang up or fold my clothes in a special way
14. I have to do things several times before I think they are properly done
15. I tend to keep on checking things more often than necessary
16. I check and re-check gas and water taps and light switches after turning them off
17. I return home to check doors, windows, drawers, etc. to make sure they are properly shut
18. I keep on checking forms, documents, cheques in detail to make sure I have filled them in correctly
19. I keep on going back to see that matches, cigarettes, etc. are properly extinguished.
20. When I handle money I count and recount it several times
21. I check letters carefully many times before posting them
22. Sometimes I am not sure I have done things which in fact I know I have done
23. When I read, I have the impression I have missed something important and must go back and re-read the passage at least two or three times
24. I imagine catastrophic consequences as a result of absentmindedness or minor errors which I make
25. I think or worry at length about having hurt someone without knowing it.
26. When I hear about a disaster, I think somehow it is my fault
27. I sometimes worry at length for no reason that I have hurt myself or have some disease
28. I get upset or worried at the sight of knives, daggers, and other pointed objects.
29. When I hear about suicide or crime, I am upset for a long time and find it difficult to stop thinking about it
30. I invent useless worries about germs and disease
31. When I look down from a bridge or a very high window, I feel an impulse to throw myself into space
32. When I see a train approaching, I sometimes think I could throw myself under it’s wheels
33. At certain moments, I am tempted to tear my clothes off in public
34. While driving I sometimes feel an impulse to drive the car into someone or something.
35. Seeing weapons excites me and makes me think violent thoughts
36. I sometimes feel the need to break or damage things for no reason
37. I sometimes have an impulse to steal other people’s belongings, even if they are of no use to me…
38. I am sometimes almost irresistibly tempted to steal something from the supermarket
39. I sometimes have an impulse to hurt defenseless children or animals.