Psychology in fhe Schools Volume 28, January I 9 9 1

RELATIONSHIPS BETWEEN CHRONOLOGICAL AGE, DEVELOPMENTAL AGE, AND STANDARDIZED

ACHIEVEMENT TESTS IN KINDERGARTEN LAURA FREBERG

Carifornio Polytechnic State University

Chronological age and developmental age have been used to identify readiness for kindergarten entrance. In the current research, chronological age and results of the Gesell School Readiness Test were evaluated as predictors of kindergarten performance as measured by the Stanford Achievement Test. Subjects were 284 children attending kindergarten in the San Luis Coastal School District during the 1986-1987 school year. Results indicate that both chronological and developmental age provide good predictors of Stanford Achievement Test performance in kindergarten. Implications of the current research for setting appropriate entrance policy were explored.

For many years, educators have sought means of determining the appropriate criteria for school readiness. In recent practice, two approaches have been widely applied: chronological age and developmental age.

Many studies have documented the finding that the younger children at each grade level have a disproportionate number of problems, both academic and social (Bigelow, 1934; Campbell, 1980; Diamond, 1983; Dickinson & Larson, 1963; DiPasquale, Moule, & Flewelling, 1980; Hall, 1963; Miller & Norris, 1967). Most states have addressed this issue by determining a legal minimum age for school entrance, although ages vary by as much as six months nationwide (Shepard & Smith, 1985). Moore and Moore (1975) reported the lack of systematic research supporting the choice of entrance dates.

The importance of developmental age in determining school readiness has been pro- moted by the Gesell Institute (Ilg & Ames, 1965; Ilg, Ames, Haines, & Gillespie, 1978). The Gesell Developmental Schedules were developed on the basis of observations of hundreds of children over a period of more than 50 years. The schedules reflect the maturational sequence of child development (Lewis, 1976). The schedules have been used to develop the Gesell School Readiness Test (GSRT), an increasingly popular tool for measuring school readiness. The majority of research regarding the efficacy of these tests has been provided by the Gesell Institute itself (Ames, Gillespie, Haines, & Ilg, 1979). The Gesell Institute recommends that children who are screened as immature for school wait a year before entrance. According to Wood, Powell, and Knight (1984), these criteria should result in one-third to one-half of chronologically eligible children being labeled unready for kindergarten.

Considering the growing popularity of the developmental approach to school readiness, there is a surprisingly small amount of supporting research. Several researchers have pointed to the need for further research regarding the validity and reliability of the GSRT (Bear & Modlin, 1987; Lewis, 1976; May, 1986; May & Welch, 1986; Wood et al., 1984).

In addition, previous investigations have failed to demonstrate strong relationships between GSRT results and later performance in school. Contrary to the assumptions of the Gesell Institute, May and Welch (1984a, 1984b) found that overplaced children (those who were entered despite having been labeled unready by the GSRT) did not in

Requests for reprints should be sent to Laura Freberg, Dept. of Psychology, California Polytechnic State University, San Luis Obispo, CA 93407.

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fact have more problems than their classmates. These same researchers were unable to document any academic advantages for those students who waited a year to enter school based on the GSRT recommendation. May (1986) compared GSRT results with later achievement measures, including the Stanford Achievement Test, and found low cor- relations. Bear and Modlin (1987) reported that the Gesell Preschool Test, which is similar to the GSRT, failed to discriminate between retained and promoted kindergarten students.

The current research provides a direct comparison between chronological age and developmental age as predictors of kindergarten achievement. The Stanford Achieve- ment Test (SAT) is used as a measure of kindergarten achievement. The current research differs from previous research (May, 1986) in that SAT scores from kindergarten are used rather than SAT performance in the third, fourth, and fifth grades.

METHOD

Subjects Subjects were 284 children attending school in the San Luis Coastal School District

in California. Students in this district come from predominantely White, middle-class homes.

Materials Developmental age was assessed using the Gesell School Readiness Test (GSRT),

published by Programs for Education, Rosemont, New Jersey. Academic achievement was assessed using the complete battery of the Stanford Achievement Test (SAT). Chronological age in years and months was noted as part of the SAT administration procedure.

Procedure The GSRT was administered as an individual interview during the May preceding

expected school entrance. All children entering kindergarten were required to take the test, District kindergarten teachers who had received training sanctioned by the Gesell Institute administered the test, usually in the presence of one parent. The SAT was administered to groups by kindergarten teachers according to the protocol specified in the SAT manual. SAT administration took place during April.

RESULTS

For purposes of data analysis, children were divided into two age groups: young (5-0 or younger at time of kindergarten entrance) or old (5-1 or older at time of kindergarten entrance). By California law, a child may enter kindergarten at the age of 4-9. However, the San Luis Coastal District has under consideration a proposal to raise the age limit to 5-0. The division of chronological age groups was for the purpose of isolating the children who would be ineligible for school entrance under the proposed age limit.

Subjects were also divided into two groups based on SAT performance: high (scores at or above the 60th percentile nationally) and low (scores below the 60th percentile nationally). Children under the 60th percentile were determined to be at risk for not succeeding in the program. This may seem high by national standards, but only 19% of the current sample scored under the 60th percentile. In addition, the mode of the current sample was a score at the 95th percentile (44 cases out of 284).

Evaluation of Kindergarten Screening 79

An agreement matrix of proportions for chronological age group and SAT perform- ance group is displayed in Table 1. A Kappa index of agreement was calculated (Cohen, 1960). Chronological age and SAT performance were significantly in agreement ( x = .2058, z = 2.57, p < .001).

Table 1 An Agreement Matrix of Proportions for Chronological Age and SAT Score

~~~ ~ ~ ~ ~

Young (< 5-0) Old (> 5-0) P (ib)

High SAT .I6 .65 (.61)* .81

Low SAT .08 (.05)* . I 1

.24 .76 Sump (i) = 1.00 P (id ~~~ ~ ~ ~

+Parenthetical values are proportions expected on the hypothesis of chance association.

As administered by the San Luis Coastal District, no numerical summary of the GSRT was provided. Instead, based on subscores, the screening teacher would make a readyhnready recommendation. These recommendations served as GSRT results for the purposes of the current research.

An agreement matrix of proportions for GSRT results and SAT performance is displayed in Table 2. GSRT results and SAT performance were significantly in agree- ment ( x = .2592, z = 2.59, p < .001).

Table 2 An Agreement Matrix of Proportions for GSRT Results and SAT Scores

GSRT GSRT P (ib) Unready Ready

High SAT .08 .74 (.70)+ .81

Low SAT .06 (.03)+ 13 .I9

.14 .86 Sump (i) = 1.00 P (ia) ~~~~ ~ ~

*Parenthetical values are proportions expected on the hypothesis of chance association.

A correlation coefficient of chronological age in months and SAT score was calculated. The correlation coefficient was not statistically significant (r = .09, t = 1.516).

DISCUSSION

The current results suggest that both chronological age and development age provide good indicators of successful kindergarten SAT performance.

The highly significant agrement index between chronological age and SAT perform- ance is probably highly dependent on the particular cut point chosen for age. This point

80 Freberg

is emphasized by the failure to demonstrate a significant correlation between chronological age and SAT score. These findings suggest that school districts would be well advised to approach changes in mandated age at entrance in a cautious rather than arbitrary manner.

May and Welch (1986) found similar placement recommendations based on age and GSRT results. They reported the largest amount of variability as occurring in the youngest age group. Taking these findings along with the current results, the most efficient strategy may be to limit entrance to those in the older age group, while administering the GSRT to the younger age group. Only those younger students determined by the GSRT to be developmentally ready would be allowed to enter school. This strategy would save districts the expense of unnecessarily testing the much larger older age group, while avoiding postponing entrance for younger students who are developmentally ready for kindergarten.

It must be noted that the subjects in the current study might not be considered a random sample of all students taking the GSRT for the given year. SAT results are not available for those students who were not entered in school based on GSRT recommen- dation. There is also some anecdotal indication that not all chronologically eligible children were screened. Some self-screening by parents of younger chidlren seems to have occurred as a result of publicity surrounding the implementation of the GSRT screening program.

It is possible that the kindergarten SAT is not the best or most sensible way to assess performance in kindergarten. Bear and Modlin (1987) found that another of the Gesell screening tests, the GPT, failed to discriminate between retained and promoted kindergarten students. This might be an outcome of more importance to children, parents, teachers, and administrators than performance during a one-week period on a standardized test. May and Welch (1984b) explored the relationship between screen- ing results and later needs for learning assistance. This would also be an outcome of interest in making a placement decision. May (1986) found no correlation between GSRT scores prior to kindergarten and SAT scores at the third, fourth, and fifth grade levels. This might indicate that the GSRT predicts performance at the kindergarten level, as shown in the current research, but not at later levels.

Further research aimed at evaluating the competence of the GSRT to predict school performance will be directed at comparing GSRT recommendations with other measures of kindergarten performance, such as report cards, referrals to special services, and social competence in the classroom. In addition, kindergarten SAT data from the students denoted as “buy-a-year” by May and Welch (1984a) will be compared with the subjects of the current research. May and Welch (1984a) were unable to demonstrate any im- provement in later SAT scores for these students. However, it is possible that the kinder- garten SAT score might reflect differences, whereas the later SAT scores did not.

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