Supports Intensity Scale®

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What makes SIS unique?

Traditionally, a person's level of developmental disability has been measured by the skills the individual lacks. SIS shifts the paradigm from lacks to needs, i.e., the Scale evaluates what practical supports people with developmental disabilities need to lead normal, independent lives.

Strengths of the SIS-A


  • Is an evidence-based assessment, whose reliability and validity have been repeatedly documented in research reports, and published in peer-reviewed journals.
  • Is a normed instrument that used a sample of unimpeachable statistical strength and greater cultural diversity than most tools developed in the US for people with intellectual and other closely related developmental disabilities.
  • Has demonstrated to accurately measure support needs across cultures and languages.
  • Is a tool that reflects a new way of thinking about supports; rather than addressing limitations—as an adaptive behavior scale would—the SIS focuses on the strengths of the individual.
  • Is consistent with the values of community inclusion, self-direction, individual choice/control, and person-centered services.
  • Allows for the addition of supplemental data collection during the assessment whose data can be stored in the data record.

Unique Features of the SIS-A

The SIS-A data can be used at the individual, agency, and systems levels. At the individual level, the SIS provides the opportunity for discussions about topics important to and for the individual and provides a comprehensive support needs profile of the individual, and is the basis for individualized, support planning for individuals with intellectual and closely related developmental disabilities.

At the agency level, SIS data forms the basis for generating staffing plans, staff training, budgeting, strategic planning, and evaluation. Aggregated data can support annual and long range planning for provider service agencies, suggest outcome targets, and assist board members to focus attention on programmatic needs.

At the systems level, jurisdictional systems may seek a more efficient use of public funds, promote flexibility in the selection of services, and ensure greater equity. SIS aggregate data has contributed one component to numerous states and provinces for their resource allocation and systems planning processes.

SIS is positive, supports-oriented, and person-centered

SIS allows professionals and family members to start the supports planning process with the goals and aspirations of the person, instead of skills and deficits. SIS also involves the person being evaluated from the beginning to the end of the planning process, making the supports assessment process inclusive and consumer-oriented.

Team and environment approach

SIS begins with an interview of the individual, with participation from a team of friends and supporters and this approach encourages a role for non-I/DD professionals. The focus of SIS is on community resources, those closest to the individual, and building on the self-identified goals of the individual.

Practical orientation

SIS gives professionals direct and reliable measures of practical supports required in daily living activities. The interview forms rank support requirements by frequency (none, once a month, and more), daily support time (none, less than 30 minutes, and more), and type of support needed (none, monitoring, verbal prompting, and more). The SIS User's Manual provides detailed instructions on how to score and administer the Scale.

Comprehensive Scoring System

The SIS interview and profile form presents assessment results in different ways. A subscale standard score indicates which of the daily activity areas require the most support. The Supports Needs Profile graphically plots these subscale scores for a quick visual overview of areas of high and low intensity support needs. Also, the SIS-A Support Needs Index provides a single score indicating overall level of supports required. A percentile ranking indicates how the individual compares to others nationally.

Scientifically valid and reliable

The SIS was extensively field tested for more than two years, making it a proven and highly reliable tool. SIS was normed on 1,306 adults who demonstrated a variety of adaptive behavior levels, levels of intelligence, secondary disabilities, living and working arrangements, ages, and ethnicities. It has been proven reliable based on five indices of reliability, and valid based on three types of validity. The strong psychometric and technical properties of the original SIS were summarized in the Supports Intensity Scale: User’s Manual. The normative information for the SIS-A and the SIS are identical as the same normative sample and process were used to inform both assessments.The standardized portion of the SIS-A has the same items, the same rating scale, and is scored in the same way as the SIS.

Other management uses

Although designed as a tool for individualized supports planning, SIS can also be used to examine support needs across comparable groups and agencies including four types of analyses:

  • Descriptive analysis of summary statistics for program planning and population projections
  • Resource allocation analysis
  • Funding analysis examining how levels of support relate to funding
  • Covariate analyses that use SIS data as statistical adjustment in program evaluation.