Adaptive Behavior Scales

The Scales of Independent Behavior - Revised (SIB-R), the Vineland Adaptive Behavior Scales, the AAMR Adaptive Behavior Scales (ABS) and the Inventory for Client and Agency Planning (ICAP) are the most widely used adaptive behavior assessments in the United States. Their popularity is owed largely to their usefulness and accuracy, derived from quality standardization and norming. The following pages describe and compare these four tests. Unless otherwise mentioned, information comes from the tests' manuals.

Adaptive behaviors are everyday living skills such as walking, talking, getting dressed, going to school, going to work, preparing a meal, cleaning the house, etc. They are skills that a person learns in the process of adapting to his/her surroundings. Since adaptive behaviors are for the most part developmental, it is possible to describe a person's adaptive behavior as an age-equivalent score. An average five-year-old, for example, would be expected to have adaptive behavior similar to that of other five-year-olds.

Behavior problems, often called maladaptive behaviors, are behaviors that interfere with everyday activities. Good adaptive behavior and a lack of behavior problems promote independence at home, at school, and in the community. Behavior problems are much more difficult to quantify than adaptive behaviors are, because they are not very developmental and because their expression varies more from day-to-day and from setting-to-setting. Behavior problems do not increase or decrease steadily with age. Nevertheless they can be measured reliably.

The purpose of measuring adaptive and maladaptive behavior is usually either for diagnosis or for program planning. The diagnosis of mental retardation, for example, requires deficits in both cognitive ability and adaptive behavior, occurring before age 18. Adaptive behavior assessment is also used to determine the type and amount of special assistance that people with disabilities may need. This assistance might be in the form of home-based support services for infants and children and their families, special education and vocational training for young people, and supported work or special living arrangements such as personal care attendants, group homes, or nursing homes for adults. Adaptive behavior assessments are often used in preschool and special education programs for determining eligibility, for program planning, and for assessing outcomes.

Standardization is the process of developing a test that reliably and validly measures a specific dimension of behavior. It involves trying out items and analyzing them; revising or discarding those that don't work, adding items where there are gaps in difficulty, and reanalysis. It also involves developing standard testing procedures and materials. The result should be a test that reliably measures the same thing the same way each time, so that scores are comparable. A standardized test should also demonstrate validity, meaning that it actually measures what it portends to measure. A test score should correlate with something in the real world.

Norming is the process of determining average scores for average people. Many tests are standardized, but few are normed because norming is an expensive process which usually means testing hundreds or thousands of carefully selected individuals -- school children throughout the U.S., for example. Norms are important because they help give test scores meaning - something to compare to. A raw score of 7, for example doesn't mean much. It means more to know that a score is at the 50th percentile for an individual of a certain age.

In norming, a large number of individuals are given a standardized test in order to determine average (normal) test scores, often averages for each age or other sub-group. This permits test scores to be compared to average, to each other on a relative basis, or to scores on other normed tests. The three major types of norm scores are age scores, percentiles, and standard scores.

Tests can be normed on more narrowly defined populations, although the usefulness of these scores varies with the definition of the norm group. "Developmentally disabled adults," for example, can range from profoundly mentally retarded to almost average. Norms on such a loosely defined group are equally loosely defined. Therefore the following comparisons differentiate norms for average non-handicapped individuals from data on supplemental standardization groups of people with handicaps.

Scales Compared

This paper compares the four most widely used tests of adaptive and maladaptive behavior. Each test relies on a respondent such as a parent, teacher, or care-provider to provide information about an individual being assessed. With some tests respondents are interviewed; with other tests respondents fill out a response booklet directly.

The Scales of Independent Behavior (SIB-R), revised in 1996, is distinguished by several features. It contains an excellent behavior problem scale in addition to its adaptive behavior assessment, and provides a unique score which reflects overall independence based on adaptive and maladaptive behavior combined. It has norms that extend beyond adolescence -- from 3 months to over 80 years. It can be administered either as a questionnaire or as a carefully structured interview, with special materials to aid the interview process. It has a short form, a short form for children, and a short form adapted for individuals who are blind.

The Vineland Adaptive Behavior Scales, a revision of the original Vineland Social Maturity Scale, are distinguished by their heritage as well as by good norms and psychometrics. The Vineland assesses personal and social skills, with norms up to 18 years old. Two interview editions, one with 577 items, the other with 297, gather information through semi-structured interviews. Both include a Motor Skills Domain for children less than 6 years old and an optional Maladaptive Behavior Domain for children age 5 through 18.

The Vineland Manual states that the Survey and Expanded forms must be administered by a psychologist, social worker, or other professional with a graduate degree and training in interview techniques. Although the assessment booklets are quite straight-forward and well organized (adaptive items are ordered by difficulty and scored never, sometimes, or usually), the interview process is somewhat complex and time-consuming. The interviewer is instructed to never read items to a respondent and to never permit a respondent to read any of the items, but rather to ask general questions followed by further probes when necessary. Appendices (26 and 52 pages) describe scoring criteria for each item. A similarly administered maladaptive behavior section contains a list of 27 minor maladaptive behaviors such as Sucks thumb or fingers. Nine more serious behaviors, not normed for non-handicapped individuals, can be scored by frequency and noted for informational purposes as severe or moderate.

The Vineland also offers a Classroom form for children age 3 through 12. This form is a questionnaire booklet that is completed directly by a teacher. Administration of this form, which has a smaller standard error of measurement than the interview forms, requires neither interview training nor a graduate degree. The Classroom Form does not include a maladaptive behavior component.

The AAMR Adaptive Behavior Scale 2nd edition (AAMR ABS) was developed by the American Association on Mental Retardation, the oldest professional organization devoted to mental retardation in the United States. Its adaptive behavior scale is available in two forms -- one for School, the other Residential and Community Settings. Both versions assess the manner in which individuals cope with the natural and social demands of their environment.

The AAMR ABS adaptive behavior domains have two types of items, either "circle the highest level" or "yes/no." Some items are worded negatively, and can be somewhat confusing. A child who uses a napkin, for example, would be rated "no" on the item Does not use a napkin." Maladaptive behavior items are rated never, occasionally, or frequently. There is, however, no measure of relative severity. Items such as Blames own mistakes on others receives the same weight as Chokes others.

The unidimensionality of several AAMR ABS domains is questionable. A unidimensional scale is one that measures a single dimension of knowledge or behavior, important in order to define what is being measured. A mathematics test score would be difficult or impossible to interpret if the test included a smattering of social studies questions. Likewise the AAMR Physical Development Domain score, to pick one example, is difficult to interpret because in addition to items on balance, walking, running, and arm-hand use, are items on vision and hearing, all scored together.

The Inventory for Client and Agency Planning (ICAP) is a 16 page booklet that, in addition to measuring adaptive and maladaptive behavior, also gathers a compact but comprehensive set of information about an individual's demographic characteristics, diagnoses, support services needed and received, and social/leisure activities. Scoring and database software prints reports and maintains current and historical information on up to 10,000 clients as well.

The ICAP's adaptive and maladaptive behavior sections contain items selected from the SIB-R, described above, with norms for infants through adults. Like the SIB-R, the ICAP also yields a Service Score, a combined measure of adaptive and maladaptive behavior indicative of overall need for care, supervision, or training. Because the ICAP is shorter than the SIB-R, its reliability is slightly less, but still excellent when compared to other scales.