SIS. Supports Intensity Scale. International Psychometric properties

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1 SIS Supports Intensity Scale International Psychometric properties Similarities and differences between original US version and Dutch, Italian, French and Spanish translations Wil Buntinx, PhD / FAAIDD IASSID Halifax July 10, 2012

2 Central question: Is the SIS a reliable and valid tool across countries and cultures? Translating is not enough validity and reliability should be examined in representatieve groups for each language and culture. Standards for Educational and Psychological Testing, Washington: APA 1999 Is the SIS a valid and reliable instrument to assess supports intensity needs of persons with ID in other countries than the US? Translations considered: - Dutch (Flanders-Belgium / the Netherlands) - Italian - Spanish (Catalan) - French (Canadian)

3 SIS relilability Internal consistency (α) split-half SEM Dutch Standardization Flemish standardization USA 1 Italy Spain SIS subscale number of items α SEM splithalf splithalf α SEM α α α Section 1 A B C D E F SIS Index , , (SIS internal consistency = excellent)

4 SIS reliability Test-retest - Inter-interviewer - Inter-respondent - client-staff Test-retest Inter-interviewer Clientstaff Interrespondent USA 1 Canad Spain USA 1 USA 2 Canad Spain USA 2 Canad Dutch SIS subscale section 1 A B C D E F SIS Index Interval 3 weeks 3 weeks 3 weeks <1 week <1 week <1 week <1 week <1 week <1 week N Effect of TRAINING SIS interviewers! no training (USA1) versus training (USA2) Client staff respondent correspondence

5 SIS psychometric characteristics Reliability summary Cronbach α (int. consistency):.99 (all subscalesα>.93) Test-retest: Inter-respondent: Inter-interviewers: [.59] Special case: correlation between client response and professional staff / parent responses when interviewing the client, always use more information sources in order to get a reliable estimate of intensity of supports need.

6 SIS psychometric characteristics Validity Content validity content validity of translated SIS = similar to original ( universal construct of support need ) Criterion validity = independent judgment of intensity of needed supports On a 5 point Likert scale per domain and full section 1 scale

7 Criterion validity correlations between SIS scores and independent judgment of support need intensity by direct support staff SIS section 1 subscale Independant judgment staff Independent judgment staff Independent Judgment staff Concurrent validity ELIDA scale USA 1 Dutch pilot study Spanish study Flemish stand. group A B C D E F SIS Index N ,211

8 Construct validity Subscale intercorrelations SIS Section 1 A B C D E F A B.84/.84/.50 C.57/.77/.43.66/.85/.45 D.59/.73/.30.62/.77/.34.85/.82/.54 E.86/.85/.56.84/.86/.52.70/.85/.40.71/.79/.48 F.70/.76/.46.77/.85/.51.77/.84/.51.77/.82/.46.82/.85/.51 SIS Index.86/.90/.60.89/.94/.59.86/.93/.62.86/.89/.59.93/.94/.62.91/.93/.59 Dutch / Flemish study / American original study

9 Construct validity Correlation SIS VABS / ICAP SIS section 1 VABS total score VABS total score ICAP Score USA 1 NL/VL Spain A B C D E F SIS Index N VABS: Vineland Adaptive Behavior Scale ICAP: Inventory for Client and Agency Planning

10 Construct validity Correlations between SIS Section 1 subscales and age & gender (Spain) Home living Community living SUBSCALES Lifelong learning Employment Health And safety Social activities AGE GENDER Correlations between SIS Section 1 subscales and gender in Dutch version is.00! (N=4,211)

11 mild moderate severe profound Level of Intellectual Functioning SIS Index Distribution of SIS Index scores In individuals with ID Dutch Flemish standardization Group mean Construct validity Are traditional levels of functioning a good indicator of support needs???? Not at all!!! In individual cases, level of intellectual functioning is not a good predictor of support needs!

12 Factor validity Spanish and Dutch factor analysis studies confirm 6 factor structure of section 1 Exploratory factor analysis in Section 1 also shows a solide 6 factor structure that corresponds with subscales A-F Extra finding: when section 2 is included in the factor analysis a 7 factor SIS is a also validly demonstrated! Extra finding: in resource allocation tasks, a short form of the SIS (22 items) showed to be valid, reliable and useful in populations with other than intellectual disability (Bossaert et al., 2009; Kuppens et al., 2010; also Gomiero et al. 2011)

13 Conclusion and discussion The SIS fully maintains its high internal consistency throughout all translations. Inter-interviewer / inter-respondent correspondences are good in several international samples. Construct validity = subscale intercorrelations are higher in translated versions (i.e. Dutch & Spanish studies) as compared to US. Are small differences in averages and SD of SIS raw scores related to standardization sample characteristics? difficult to tell... A special international study would be welcome to see how these differences can be explained. So far, no independent (re)constructions of SIS in other cultures have been made. However, some test accreditation councils do stress this necessity (NL). A short form of SIS is likely to maintain all psychometric properties of the full scale in other than intellectually disabled populations.

14 Wil H.E. Buntinx Governor Kremers Center at Maastricht University The Netherlands Contact: A full list of references is included in a document at SIS For international SIS basic training, SIS train-the-trainer courses, and support need assessment consultance in clinical and managerial practices, consult:

3d IASSID Europe conference, Rome October 20-23, 2010 session

3d IASSID Europe conference, Rome October 20-23, 2010 session 8.8 21.10 Psychometric properties of the Supports Intensity Scale (SIS): an international review W. Buntinx (w.buntinx@beoz.unimaas.nl), B.