The assessment triangle framework (cognition, observation, and interpretation) proposed by the National Research Council (2001) is helping instructors understand how to measure what students know and to identify difficulties to address in order to advance students' learning. Another resource to help instructors develop their own assessments to find out what students know about experimentation is the three-step assessment development and evaluation process we published (Dasgupta, Anderson, and Pelaez, CBE Life Sciences Education 15(2) , 2016 doi:10.1187/cbe.15-03-0077). Please suggest other published resources that people can refer to in thinking about assessment design and implementation.