Assessment is a key lever for educational improvement. Assessments can be used to monitor, signal, and influence science teaching and learning -- provided that they are of high quality, reflect the rigor and intent of academic standards, and elicit meaningful student performances. Since the release of "A Framework for K-12 Science Education" and the Next Generation Science Standards (NGSS), assessment systems are fundamentally changing to surface students' use of disciplinary core ideas (DCI), scientific and engineering practices (SEP), and crosscutting concepts (CCC) "together in service of sense-making" about a phenomenon or problem. As states and districts develop new assessment systems, they need support for developing assessments that balance the vision and integrity of multi-dimensional standards with ensuring that they are sensitive to varying levels of student performance. This brief describes a new approach to capturing and communicating the complexity of summative assessment items and tasks designed for three-dimensional standards that can be used to ensure that all learners can make their thinking and abilities visible without compromising the rigor and expectations of the standards. This draft framework for evaluating cognitive complexity in science assessments intentionally builds on expectations for student performance provided by the "Framework for K-12 Science Education" and standards like the NGSS. This complexity framework can be used to determine the degree to which an assessment task asks students to engage in sense-making, a cornerstone of NGSS assessments and performance. [Achieve developed version 1 of this complexity framework for science assessment in collaboration with Miray Tekkumru-Kisa. Additional funding for this work was provided by Chevron.]