Gesell Developmental Schedules

The Gesell Developmental Schedules is also known as GDS, the Gesell Maturity Scale, the Gesell Developmental Observation, and the Yale Tests of Child Development is a developmental measure. The purpose of the scale is to measure the development of infants and young children.

History
The Gesell Developmental Schedule was first published in 1925. Throughout the years, it has been subjected to extensive research and has subsequently been refined and updated in 1940, 1965, 1979, and in 2011. Today, it is one of the oldest and most established intelligence measures of infants and young children, being the leading infant intelligence measure from the 1930s through the 1960s. Additionally, the Gessel Developmental Schedule was nothing short of a breakthrough in infant ability testing when it was first constructed- the first of its kind, actually.

The original scale was based on the normative data that was collected from a carefully conducted longitudinal study of early human development. The study focused on the various stages of developing and how they unfolded over time.

In March 2010, the Gesell Institute completed a nationwide study which included some 1,300 assessments of infants and young children in the hopes of gathering supportive data.

The Scale
The Gesell Developmental Schedules claim that an appraisal of the developmental status of infants and young children can be made, with the age range being 2.3 months to 6.3 years. Like other procedures based on developmental data, the Gesell Developmental Schedule believes that human development unfolds in stages, or in sequences over a given time period. These stages were considered milestones, or the manifestations of mental development. Some examples are:


 * "When the infant first rolls from back to stomach unassisted"
 * "When the child first utters words"
 * "When the child learns to walk"

The Gesell Developmental Schedule was then able to compare the infant or child's rate of development to a norm that was derived from a previous longitudinal study (see history, above). Accordingly, the scale would purportedly be able to show that infants and young children who demonstrate behaviors or responses more typical of an older chronological age would have higher intelligence.

Additionally, the Gesell Developmental Schedule has moved beyond merely identifying high-intelligence children and has become a research tool. Researchers use the scale today to assess infant intellectual development after:


 * "Exposure to mercury"
 * "Diagnoses of abnormal brain formation"
 * "In utero diagnoses of hyperthyroidism"
 * "In assessing infants with autism"

Further, the scale does seem to assist in revealing subtle deficits in infants that may occur.

The Gesell Development Schedule operates off what is known as an individual's developmental quotient, or otherwise known as DQ. The DQ is determined according to the scores of the test and is evaluated by ascertaining whether or not the infant or child is displaying the appropriate behavior for the age (The individual's developmental quotient is a parallel to the mental age (MA) concept). In turn, The DQ is used as part of an IQ formula:

IQ = Development Quotient / Chronological Age X 100

Or, IQ = DQ / CA X 100

Drawbacks
Although the Gesell Development Schedule has had many years of extensive use and much revision, the scale suffers from many psychometric weaknesses, and has fallen short of the acceptable standards of psychometrics. As a result, interest in and use of the scale has fallen over the years.

The first issue with the scale is that the standardization sample is quite inadequate. Although data was gathered by the Gesell Institute in 2010 to find support, the sampling merely improves the standardization of the scale. Secondly, There is no evidence of reliability or validity in the test manual. Third, the test directions are sometimes vague and scoring procedures are questionable – although the newest scale does provide an updated and improved screening instrument. Fourth, the scale does not have sufficient proof that it can predict future intelligence – although it can obtain an early estimate of possible mental retardation.