What is the SIB-R? The Scales of Independent Behavior, Revised, explained
The SIB-R (Scales of Independent Behavior, Revised) measures adaptive and problem behavior from 3 months to 80+ and yields a Support Score for planning. (152 chars)
Dr. Russell T. WarneChief Scientist
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The SIB-R (Scales of Independent Behavior, Revised) is a "norm-referenced" assessment, meaning it compares a person to a representative national sample, that measures adaptive behavior and problem behavior in people from 3 months to more than 80 years of age. Published in 1996 by Robert Bruininks, Richard Woodcock, Richard Weatherman, and Bradley Hill, and available today from Riverside Insights, the SIB-R rates how independently a person handles everyday tasks at home, at school, at work, and in the community. It also rates eight categories of problem behavior and combines both types of information into a Support Score, an estimate of the level of help a person may need. This article covers what the SIB-R measures, how it is administered and scored, who uses it, and how it fits alongside intelligence testing.
What the SIB-R measures
"Adaptive behavior" is the set of practical, social, and conceptual skills a person actually uses in daily life. It is a different question from what a person can do on a cognitive test under ideal conditions. The SIB-R measures adaptive behavior with 14 subscales that, according to a National Research Council review of adaptive behavior instruments, fall into four major clusters and combine into a full-scale score called "Broad Independence."
• Motor skills: movement-based tasks involved in everyday activity, from early physical milestones to coordinated adult skills.
• Social interaction and communication skills: getting along with other people and understanding and expressing language.
• Personal living skills: looking after oneself and one's immediate surroundings in daily routines.
• Community living skills: functioning beyond the home, in settings such as school, work, and the wider community.
Each adaptive behavior item describes a task. According to the Texas Education Agency's statewide autism training site, items are rated on how completely and independently the person performs the task, with no help or supervision. A respondent who knows the person well, such as a parent, teacher, or caregiver, provides the ratings on a four-point scale that runs from never or rarely performs the task to performs it very well, always or almost always, without being asked.
Problem behavior scales and the Support Score
Adaptive skills are only part of the picture of independent functioning. The SIB-R also asks the respondent about eight areas of problem behavior, and each reported behavior is rated for both frequency and severity. These ratings produce four "maladaptive behavior indexes": a General Maladaptive Index plus Internalized, Asocial, and Externalized indexes.
The maladaptive indexes are reported on a scale where scores between +10 and -10 fall in the normal range. Progressively lower scores are described as marginally serious (-11 to -20), moderately serious (-21 to -30), serious (-31 to -40), and very serious (below -41). In plain terms, the more frequent and severe the problem behavior, the lower the index falls.
The SIB-R's most distinctive feature is the Support Score. The Texas Education Agency describes it as a weighted measure of adaptive and maladaptive behavior that indicates the approximate level of support a person may need to be independent in different areas. The logic is practical: two people with similar adaptive skills may need very different levels of supervision if one of them shows serious problem behavior. Combining both scales into one planning-oriented score is unusual among adaptive behavior measures, and it is a major reason disability service agencies have used the SIB-R and its companion instrument, the ICAP, in service-level decisions.
Forms, administration, and scores
The publisher, Riverside Insights, offers the SIB-R in three forms, and each can be given either as a structured interview or as a checklist the respondent completes.
• Full Scale: the complete 14-subscale battery, taking about 45 to 60 minutes, used when a thorough adaptive behavior evaluation is needed.
• Short Form: a screening version with 40 items drawn from across the scale, taking about 15 to 20 minutes.
• Early Development Form: a brief form, also about 15 to 20 minutes, designed for young children and for older individuals whose developmental functioning is below the level typical of an 8 year old.
Scores compare the individual to others of the same age. The cluster scores and the Broad Independence composite are reported as "standard scores" on the familiar mean-100 scale, where about two thirds of the population scores between 85 and 115. According to the National Research Council, the SIB-R was normed on 2,182 people sampled to match the general population of the United States, with stratification by gender, race, Hispanic origin, occupation, geographic region, and community size. Peer-reviewed summaries report strong reliability, with internal consistency coefficients in the .84 to .98 range for the normative sample and even higher values among children with intellectual disabilities.
Who uses the SIB-R, and for what
The SIB-R's authors designed it for individual evaluation, program planning, placement decisions, and assessing service needs. In practice, it shows up in two main contexts.
The first is eligibility evaluation for intellectual and developmental disability services. The American Association on Intellectual and Developmental Disabilities defines intellectual disability by significant limitations in both intellectual functioning and adaptive behavior, originating before age 22. The American Psychiatric Association describes the same dual requirement and notes that diagnosis involves a standardized adaptive behavior measure scored well below the population norm, alongside intelligence testing and clinical judgment. An instrument like the SIB-R supplies the adaptive behavior half of that picture, which no IQ test can provide.
The second is support planning. Because the Support Score translates adaptive and problem behavior ratings into an estimate of needed assistance, state disability agencies have published detailed guidance on completing the SIB-R item ratings and those of the related ICAP when determining levels of service. The instrument's range from infancy through late adulthood also makes it usable across a lifespan of planning decisions, from early intervention through supports for older adults.
How the SIB-R relates to the Vineland-3, the ABAS-3, and the Woodcock-Johnson family
The SIB-R belongs to the same family of instruments as the Woodcock-Johnson tests. The National Research Council notes that the original Scales of Independent Behavior was developed as a component of the Woodcock-Johnson Psycho-Educational Battery, and Richard Woodcock is a co-author of the SIB-R itself. If you want the cognitive side of that family, our overview of what the Woodcock-Johnson test measures explains the ability and achievement batteries. The SIB-R covers the everyday-functioning side that those cognitive batteries deliberately leave out.
Among adaptive behavior measures, the most common alternatives are the Vineland-3 and the ABAS-3. The Vineland-3 uses interview and rating forms and is a fixture in autism and intellectual disability evaluations. The ABAS-3 uses rating forms organized around the conceptual, social, and practical skill areas that appear in diagnostic definitions. The SIB-R's distinctive contributions are its integrated problem behavior scales, its Support Score, and its lineage in the Woodcock-Johnson measurement tradition. In practice, the choice among the three often comes down to agency requirements, the evaluator's training, and which respondents are available.
Adaptive behavior and intelligence answer different questions
Adaptive behavior and intelligence are related, and the strength of that relationship changes with age. A National Research Council review reported that SIB-R adaptive behavior scores correlated .78 with IQ among children ages 5 to 12, but only .20 among adolescents and adults ages 13 to 90. By adulthood, knowing someone's IQ tells you fairly little about how independently they manage daily life, which is exactly why diagnostic frameworks require both kinds of evidence rather than letting one stand in for the other.
For the intellectual side of the picture, adults now have a well-built online option. The RIOT IQ test (Reasoning and Intelligence Online Test), developed by RIOT IQ with psychometrician Dr. Russell T. Warne, measures intelligence in adults 18 and older through 15 subtests spanning six cognitive indices: verbal reasoning, fluid reasoning, spatial ability, working memory, processing speed, and reaction time. It takes about 52 minutes and reports scores on the same mean-100, standard-deviation-15 scale used by the SIB-R's composites. It does not measure adaptive behavior, and it does not replace an individually administered diagnostic evaluation. As a rigorous measure of general cognitive ability, though, it is a strong starting point, and you can take the RIOT IQ test at riotiq.com.
Frequently asked questions
Is the SIB-R an IQ test?
No. The SIB-R measures adaptive behavior and problem behavior, meaning what a person actually does in everyday life. IQ tests measure cognitive ability. Diagnostic evaluations for intellectual disability use both.
What ages does the SIB-R cover?
The SIB-R is normed for people from 3 months of age to over 80 years, which allows the same instrument to be used from infancy through late adulthood.
How long does the SIB-R take?
The publisher reports about 45 to 60 minutes for the Full Scale and about 15 to 20 minutes for the Short Form or the Early Development Form.
What is the SIB-R Support Score?
It is a weighted score that combines adaptive behavior ratings with problem behavior ratings to indicate the approximate level of support a person may need to function independently in different areas.
Can the SIB-R alone diagnose intellectual disability?
No. Both AAIDD and the American Psychiatric Association require significant limitations in intellectual functioning and in adaptive behavior, with onset during the developmental period. That requires an intelligence test, an adaptive behavior measure, and clinical judgment together.
Who answers the SIB-R questions?
A respondent who knows the person well, such as a parent, caregiver, or teacher. The examiner can administer the items as a structured interview or have the respondent complete a checklist.
2. Texas Statewide Leadership for Autism Training, Texas Education Agency. (n.d.). Scales of Independent Behavior – Revised. txautism.net
3. National Research Council. (2002). The role of adaptive behavior assessment. In Mental retardation: Determining eligibility for Social Security benefits. National Academies Press. ncbi.nlm.nih.gov
4. National Research Council. (2002). The relationship of intelligence and adaptive behavior. In Mental retardation: Determining eligibility for Social Security benefits. National Academies Press. ncbi.nlm.nih.gov
5. Ewles, G., Clifford, T., & Minnes, P. (2014). Predictors of advocacy in parents of children with autism spectrum disorders. Journal on Developmental Disabilities, 20(1), 73–82. oadd.org
6. American Association on Intellectual and Developmental Disabilities. (n.d.). Defining criteria for intellectual disability. aaidd.org
7. American Psychiatric Association. (n.d.). What is intellectual disability?. psychiatry.org
Hero photo: House key with a house-shaped keychain in a front-door lock. Photo by Shixart1985, CC BY 2.0, via Wikimedia Commons.
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