This toolkit provides a practical guide for selection and adaptation of child development measurements for use in low- and middle-income countries. Users can follow the proposed step-by-step process to select, adapt, implement, and analyze early childhood development data for diverse purposes and projects. Researchers, evaluators, and program personnel from various disciplines interested in assessing early childhood development in low- and middle-income countries will find the book useful for planning and evaluating interventions, monitoring development over time, or conducting a situation analysis.