Bayley Scales of Infant Development:
The Bayley Scales of Infant Development measure mental and physical, as well as emotional and social, development. The
test, which takes approximately 45 minutes, is administered individually by having the child respond to a series of
stimuli. The Mental Scales, which measure intellectual development, assess functions such as memory, learning,
problem-solving ability, and verbal communication skills. The Motor Scales evaluate the child's ability to sit and
stand, perform other activities requiring coordination of the large muscles (gross motor skills), and perform more
delicate manipulations with fingers and hands (fine motor skills). Finally, the Infant Behavior Record (IBR) assesses
the child's social and emotional development through a standardized description of his or her behavior during the
testing session. Scores are measured against norms for each of the 14 different age groups. Often, the Bayley scales
are used to determine whether a child is developing normally and provide for early diagnosis and intervention in cases
of developmental delay, where there is significant tardiness in acquiring certain skills or performing key activities.
Additionally, they can be used to qualify a child for special services and/or demonstrate the effectiveness of those
Differential Ability Scales (DAS):
The Differential Ability Scales is an individually administered battery of cognitive and achievement tests for children and
adolescents aged 2 years, 6 months through 17 years, 11 months. It is divided into three levels:
The DAS was designed to measure specific, definable abilities and to provide interpretable profiles
of strengths and weaknesses. The DAS is considered suitable for use in any setting in which the cognitive
abilities of children and adolescents are to be evaluated, although many of the DAS subtests are not appropriate for students
with severe sensory or motor disabilities. The cognitive battery focuses on reasoning and conceptual abilities and
provides a composite standard score, the General Conceptual Ability (GCA) score.
- Lower Preschool (ages 2 years, 6 months through 3 years, 5 months)
- Upper Preschool (aged 3 years, 6 months through 5 years, 11 months)
- School-Age (6 years, 0 months through 17 years, 11 months)
The DAS contains a total of 20 subtests grouped into Core Cognitive, Diagnostic, or Achievement tests. The Core Cognitive
subtests are those used to compute the GCA and cluster scores, while the Diagnostic subtests are those considered important
and useful in the interpretation of an individual's strengths and weaknesses, but which do not assess "complex mental
processing" well. It has a built-in mechanism for assessing significantly delayed children who are over the age of 3˝ years. It
can also provide information comparable to other similar instruments in about half the time.
Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R)
The WPPSI-R is an individually administered, norm-referenced, standardized test for children ages 3 years to 7
years 3 months to assess intelligence. It is organized into 2 groups of subtests, perceptual-motor (performance) and
verbal. These yield the Performance scale and Verbal scale IQ scores. These two IQ scales combine to yield a Full
Scale IQ, with a mean of 100 and a standard deviation of ±15. The WPPSI-R has one group of perceptual-motor (Performance)
subtests and a second group of Verbal subtests. The child responds to the Performance subtests with motor responses such
as pointing, placing or drawing. The Verbal subtests require verbal responses from the child. The starting points and
discontinuing rules are given in the directions for each subtest. The subtests are customarily started according to the
child's age. The discontinue rule is usually a certain number of consecutive failures. The WPPSI-R has 12 subtests, 2 of
which are optional. This instrument cannot be used with severely disabled children (IQ's below 40) and, with younger
children, may need to be administered over two sessions due to the length of time required to complete the assessment.
Wechsler Intelligence Scale for Children-III (WISC-III)
This intelligence test is the universal standard which School Psychologists use most often. This version of the Wechsler
is standardized for children from age 6 to 16. The test, itself, is divided into two main sections. The Verbal Scale
measures how well children are able to express themselves verbally and how well they are able to understand what is being
said to them. The Performance Scale measures the nonverbal areas of being able to perceive spatial relationships; such as
in putting puzzles together, and being able to transfer visual information rapidly. Using test interpretation, the three
I.Q. scores and the specific pattern of strengths and weaknesses indicate how well the child is able to learn and whether
there are any specific learning disabilities. This information is then used to predict at what academic level the child
should be functioning. In this way, diagnoses of learning impairments are possible.
Wechsler Adult Intelligence Scale - Revised (WAIS-R)
One of the most frequently used tests of adult intelligence, it is based upon a series of subtests with two general categories
of items, verbal and performance. Verbal items deal with general information, vocabulary, arithmetic tests, comprehension,
similarities, analogies, etc.; performance items deal with picture arrangement and completion, block designs, spatial relations,
and the like. The test was revised in 1981 and is familiarly known as the WAIS-R, pronounced 'waiss-are.' The WAIS-R covers an
age range of 16 years, 0 months to 74 years, 11 months.
Stanford-Binet Intelligence Scale 4th Ed.
This intelligence test is also considered to be a standard tool of many School Psychologists. This test has been fairly
recently revised and now provides multiple I.Q. scores (called S.A.S.'s) instead of a single I.Q. score, as before. In
addition to being able to measure the verbal and nonverbal areas of a child's development, the Binet also provides a
quantitative score, measuring the child's mathematical reasoning, and a memory score, measuring the child's short-term
memory. (While the Wechsler scales also have subtests which measure these areas, they do not provide I.Q. scores isolating
these abilities.) The materials in this test are very appealing to children. The child has little chance to become bored
with this test since the activities are changed frequently. The test is somewhat cumbersome for the psychologist to administer.
For that reason, many psychologists prefer the Wechsler scales instead. However, there are instances where it is very
helpful to have another highly standardized and reliable tool to measure a child's intelligence. The Binet fills this need
McCarthy Scales of Children's Abilities
The McCarthy tests children ages 2˝ to 8˝. The purpose of the test is to evaluate the general intelligence level of children.
It also identifies strengths and weaknesses in several ability areas. These areas include: verbal, perceptual-performance,
quantitative, memory, motor, and general cognitive skills.