Abstract
Ecological validity is an important construct in the assessment of young children. The argument is made that using environmentally based assessment practices as well as understanding the child's ecology will help assure that assessments are carried out in an ecologically valid manner. The discussion focuses on play-based assessment, curriculum-based assessment, and dynamic assessment. Each of these approaches is based on authentic procedures and is typically carried out in the child's natural environment. In addition, there is a discussion of how specific environments can be delineated as well as stressing the importance of developing operational definitions of specific skills in the natural environment.