Because learning does not occur in a rigid sequence of skill acquisition and because wide variability is normal, it is inappropriate to determine school entry on the basis of acquiring a limited set of skills and abilities. Schools may reasonably expect that children entering kindergarten will be active, curious, and eager to learn. They will know some things about themselves, and will be interested in making friends and sharing experiences with them. Although gaining in self-control, kindergarten children’s enthusiasm will sometimes overwhelm them, as, for example, they call out an answer before the teacher calls on them.
It is often assumed that tests exist to reliably determine which children are “ready” to enter school. Because of the nature of child development and how children learn, it is extremely difficult to develop reliable and valid measures of young children’s abilities. Preschool children, by nature, are not good test-takers. When tests are used to make decisions that have significant impact on children’s lives, such as denial of entry or assignment to a special class, the tests must offer the highest assurance of reliability and validity. No existing readiness measure meets these criteria (Meisels, 1987). Therefore, the only legally and ethically defensible criterion for determining school entry is whether the child has reached the legal chronological age of school entry [Auntie's note: italics are original]. While arbitrary, this criterion is also fair.