In this chapter, the authors outline an approach to assessing complex constructs supported by psychological science and research. This approach is informed by their background as psychologists but is general enough to incorporate other disciplinary approaches as well. They identify this approach as TAIM (Theory, Activities, Indicators, Multiple Measures) to highlight the main assumptions of the approach. The authors believe that "theory" and research should inform assessment throughout the process, that clarity on intentional instructional "activities" is essential, that definitions of outcomes are not complete without specifying "indicators," and that complex outcomes need "multiple measures." Their background as psychologists informs not only each of these assumptions but also the broader framework of the TAIM approach. (Contains 1 figure.)