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Padua Inventory - Washington State University Revision
Supplemental for HD
Short Description of Instrument
Summary/Overview of Instrument: 39 item inventory of 5 factors in Obsessive Compulsive Disorder (OCD).
Construct measured: Obsessive Compulsive Disorder (OCD). Note this revision was done to ensure the scale was specific to OCD, and did not measure worry, which was an issue with the original Padua Inventory.
Generic vs. disease specific: Generic OCD scale, not specific to HD.
Intended use of instrument/purpose of tool: Not specified.
Means of administration: Paper and Pencil.
 Location of administration: Clinic or home.
Intended respondent: Patient.
# of items: 39 items.
# of subscales and names of sub-scales: 5 – Contamination Obsessions and Washing Compulsions; Dressing/Grooming Compulsions; Checking Compulsions; Obsessional Thoughts of Harm to Self/Others; Obsessional Impulses to Harm Self/Others.
Strengths: Self report.
Weaknesses: May be issues about whether constructs hold. See Sascha Gönner, Willi Ecker, and Rainer Leonhart. The Padua Inventory: Do Revisions Need Revision? Assessment March 2010 17: 89-106.
Psychometric Properties
Reliability: Test-retest or intra-interview (within rater) reliability (as applicable): test-retest correlation for the total PI-WSUR was 0.76 with the values for the 5 subscales varying from 0.61 for the OTAHSO subscale and 0.84 for the OITHSO subscale.
Inter-interview (between-rater) reliability (as applicable): Not applicable- only patient reports symptoms on the scale.
Internal consistency: Not available.
Statistical methods used to assess reliability: test – retest correlation with Bonferroni correction.
Validity: Several articles available on validity, (e.g. Burns, Formea, Keortge& Sternberger, 1995; Sanavio, 1988; Sternberger & Burns, 1990, 1991; Van Oppen, 1992). This instrument has not been validated in HD.
Content validity: Principal component analysis.
Construct validity: correlations showed stronger relationship to items within scale than to items on a Worry scale (Burns et al, 1996).
Sensitivity to Change/ Ability to Detect Change (over time or in response to an intervention): Not studied.
Known Relationships to Other Variables (e.g. gender, education, age, etc): There is some gender difference on subscales with Women scoring significantly higher than men on the OTAHSO (3%), COWC (<1%), the DRGRC (< 1%) subscales, and with men scoring higher than women on the OITHSO (3%) subscales.
Diagnostic Sensitivity and Specificity, if applicable (in general population, HD population- premanifest/ manifest, other disease groups): Would be best for premanifest and early symptomatic groups; length of scale may limit use in more cognitively impaired populations.
Scoring: (include reference to detailed scoring instructions, including calculation of a total score and subscale scores, and any limitations of scale or scoring posed by item nonresponse): Each item is rated on a 5-point scale according to the degree of disturbance caused by the thought or behavior (0 = "not at all" to 4 = "very much"). Subscales are simply scored by summing scores for all items included in the subscale.
Standardization of scores to a reference population (z scores, T scores, etc): Burns et al, 1996 reference provides a table with normative data on the PI--WSUR for the sample of 5010 individuals.
If scores have been standardized to a reference population, indicate frame of reference for scoring (general population, HD subjects, other disease groups, etc). General population.
Burns GL, Keortge SG, Formea GM, Sternberger LG. Revision of the Padua Inventory of obsessive compulsive disorder symptoms: distinctions between worry, obsessions, and compulsions.Behav Res Ther. 1996; Feb;34(2):163-73.
Burns, Formea, Keortge & Sternberger. 1995; Sanavio, 1988; Sternberger & Burns, 1990, 1991; Van Oppen, 1992.
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