Progress monitoring tools have been shown to be essential elements in current approaches to intervention problem-solving models. Such tools have been valuable not only in marking individual children's level of performance relative to peers but also in measuring change in skill level in a way that can be attributed to intervention and development. As such, progress monitoring measures have been central to Response to Intervention (RtI) approaches. In early childhood, progress monitoring measures have only recently been applied to the process of intervention decision-making. The purpose of this article is to describe Individual Growth and Developmental Indicators, contrast them with existing approaches to assessment in early childhood, and illustrate how they can be used within a larger problem-solving model to guide intervention decisions for infants and toddlers. (author abstract)