Developmental assessment is an ongoing process of systematic observation and analysis, the purpose of which is to understand the child's competencies and resources and the caregiving and learning environments most likely to assist the child in making the best use of his or her developmental potential. For many years young children have been assessed with normative instruments that focus primarily on evaluating their intellectual development. Many myths surround the use of these instruments with very young children, including the following: intelligence can be defined and measured with confidence; intelligence test data have diagnostic relevance; early intelligence tests have predictive value; such tests are useful for assessing young children with special needs; practitioners value and use these tests in their clinical practice; and IQ tests fulfill the legal purposes and intent of public laws. Each of these statements represents a misstatement of fact, and none of them has a strong evidentiary basis.In place of the narrow classificatory function served by such tests, a variety of other approaches to assessing intellectual and affective development in the first three years of life are described. These instruments are consistent with a group of principles of responsive, developmentally oriented assessment that include recognizing the interdependence of development, understanding the importance of using multiple sources and multiple components in assessment, providing a meaningful sequence for assessment, respecting and evaluating child-caregiver relationships, basing assessments on a framework of typical development, emphasizing the organizational and functional capabilities of the child, focusing on the child's