Authors:
Nancy Bayley

Publisher:
The Psychological Corporation
(800) 872-1726
www.psychcorp.com

Initial Material Cost:
Complete Kit: $950 (includes manual, stimulus booklet, 25 mental scale record forms, 25 motor scale record forms, and 25 behavior rating scale record forms, visual stimulus cards, map, and all necessary manipulatives, in a soft-side carrying case)

Representativeness of Norming Sample:
The norming sample was a national, stratified random sample of 1,700 children ages 1 to 42 months. The stratifying variables were age, sex, region, race/ethnicity, and parent education. The sample consisted of 17 age groups ranging from one month among the younger children and increasing to three months among the older children, each with 100 children.

Languages:
English

Type of Assessment:
Direct child assessment

Age Range and Administration Interval:
1 to 42 months

Personnel, Training, Administration, and Scoring Requirements:
Examiner should be trained and experienced in administering and interpreting comprehensive developmental assessments. BSID-II takes 15 to 35 minutes to administer to children under 15 months and up to 60 minutes to children older than 15 months.

Summary
Initial Material Cost: 3 (> $200)
Reliability: 3 (.65 or higher)
Validity: 2 (Mental Scale .5 or higher, Motor Scale |.5 (concurrent))
Norming Sample Characteristics: 3 (normed within the past 15 years, nationally representative sample)
Ease of Administration and Scoring: 3 (requires a highly trained individual).

Description: BSID-II is an individually administered examination that assesses the developmental functioning of infants and children ages 1 to 42 months. BSID-II presents infants with situations and tasks designed to produce an observable set of behavioral responses. The observed responses are scored on complementary development scales—mental scale, motor scale, and behavior rating scale (BRS). The mental scale assesses the child’s level of cognitive, language, and personal-social development. The motor scale assesses the child’s level of fine and gross motor development. The BRS assesses the child’s behavior during the testing situation, which facilitates interpretation of the mental and motor scales. The Bayley Infant Neurodevelopmental Screener, which contains 11 to 13 items selected from BSID-II, allows programs with high caseloads to screen infants 3 to 24 months for neurological impairment or developmental delay in 10 to 20 minutes.

Uses of Information: The BSID-II was designed for use in identifying areas of relative impairment or delay, developing curricula for interventions, and assessing the outcome of such interventions. The scales should not be used to measure a child’s deficit in a specific skill area or to obtain a norm-referenced score for a child with severe sensory or physical impairments. Also, although items on the mental and motor scales for older children are similar to items found on tests of school-age abilities, the BSID-II is not intended to serve as an intelligence test.

Reliability: (1) Internal consistency (Cronbach’s alpha): averages across all age groups were .88 for the mental scale, .84 for the motor scale, and .88 for the BRS total score. (2) Test-retest reliability, with a median 4-day interval between tests for children ages 1 and 12 months: .83 for the mental scale, .77 for the motor scale, and .55 for BRS total score at 1 month and .90 at 12 months of age; for children ages 24 and 42 months: .91 for the mental scale, .79 for the motor scale, and .60 for the BRS total score. Overall, the test-retest reliability coefficients were .87 on the mental scale and .78 on the motor scale. (3) The inter-rater reliability for the mental scale was .96 and for the motor scale, .75. Interrater reliability coefficients for the IBR (now the BRS) ranged from .47 to 1.00.

Validity: (1) Concurrent validity: the correlation between BSID-II and BSID was .62 on the Mental Development Index (MDI) and .63 on the Psychomotor Development Index (PDI). The BSID-II MDI scores were found to be highly correlated and the PDI scores moderately correlated with other scales of development, language, and intelligence. The MDI was found to have a correlation of .79 with the McCarthy Scales of Children Abilities (MSCA) general cognitive index and correlations of .73, .73, and .63 with the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R) full scale IQ, Verbal IQ, and Performance IQ, respectively. The PDI was found to have a correlation of .45 with the MSCA’s general cognitive index and .41, .39, and .37 with the WPPSI-R full scale IQ, Verbal IQ, and Performance IQ, respectively. Tests found smaller correlation coefficients between BSID-II and the Differential Ability Scales and the Preschool Language Scale-3. Once again, the strength of the relationships was stronger with the MDI. Finally, tests found the BSID-II and the Denver Developmental Screening Test-II to be in agreement in classifying children approximately 80 percent of the time.

Method of Scoring: For each item, the manual provides scoring instructions. The examiner scores an item by entering one of a number of scoring options. By converting mental and motor raw scores into MDI and PDI scores, the examiner can compare a child’s performance to the performance of children of similar ages. Another table provides the age-appropriate percentile ranking for the child’s BRS score.

Interpretability: BSID-II provides instruction on how to interpret the assessment results and provides three case studies as examples. Additional information on interpreting BSID-II scores is provided in the book, Essentials of Bayley Scales of Infant Development II Assessment.

Training Support: The manual contains a chapter that provides instructions on administering and scoring the BSID-II assessments. In addition, each item in the scale has directions for administering and scoring the item.

Adaptations/Special Instructions for Individuals with Disabilities: The manual includes a section on the administration of the scales to children with one or more physical or perceptual impairments.

Report Preparation Support: The manual provides case studies that serve as examples of how information from various sources may be integrated, interpreted, and presented.

References:

Bayley, Nancy. Bayley Scales of Infant Development, Second Edition. San Antonio, TX: The Psychological Corporation, 1993.

Black, Maureen M. and Kathleen Matula. Essentials of Bayley Scales of Infant Development II Assessment. San Antonio, TX: The Psychological Corporation, 1999.