Deciding whether and how to use assessments to evaluate students' social and emotional (SE) knowledge, attitudes, and skills requires the development and critical appraisal of an assessment plan. At the state, district, and school levels, education leaders and staff can benefit from reviewing best practices and using a structured format to arrive at that decision. The sections in this decision tree describe a process for making decisions about using assessments in consideration of: (1) purpose--the why of assessment; (2) rigor--appropriate for that purpose; (3) practicalities--in consideration of rigor; (4) burden--resulting from practicality; and (5) ethics--the big picture. This document is the second component in American Institutes for Research's suite of resources, "Ready to Assess." "Ready to Assess" was designed to help decision makers and practitioners make informed and ethical assessment decisions. [For "Are You Ready to Assess Social and Emotional Development? SEL Solutions Brief," see ED577553. For "Are You Ready to Assess Social and Emotional Development? SEL Solutions Tools Index," see ED577551.]