For children ages 2:6–3:6, which instrument should be used for this age range? Bayley–III or WPPSI-III?

Frequently Asked Question:

For children ages 2:6–3:6, which instrument should be used for this age range? Bayley–III or WPPSI-III?

Answer:

Which test to use depends on your clinical judgment and the purpose of testing. Practitioners can use either or both instruments for children ages 30–42 months (2 years 6 months and 3 years 6 months). Though both measures provide an estimate of a child’s cognitive functioning, the instruments are designed for different purposes. The Bayley–III provides information about whether a child’s developmental trajectory in the cognitive domain is proceeding as expected, relative to same-age peers. It also provides this type of information for language, motor, social-emotional, and adaptive behavior domains.

The WPPSI–III is specifically designed to measure a child’s overall cognitive ability, as well as his or her cognitive ability in more specific domains (e.g., verbal, perceptual, processing speed). The Bayley–III should be used to evaluate cognitive ability in low-functioning children in this age range because it provides an extended floor. The WPPSI–III should be used to evaluate cognitive ability in high-functioning children in this age range, because it provides an extended ceiling. If results of the Bayley–III suggest delays in the cognitive domain, the WPPSI–III may provide additional information on the specific areas of cognitive ability that are problematic for the child. If an ability score (e.g., FSIQ) is required, the WPPSI–III should be used.