Lloyd Bond comments here on the Focus article in this issue of "Measurement: Interdisciplinary Research and Perspectives". The Focus article is entitled: "How Task Features Impact Evidence from Assessments Embedded in Simulations and Games" (Russell G. Almond, Yoon Jeon Kim, Gertrudes Velasquez, and Valerie J. Shute). Bond begins his comments by observing that the Focus article is an ambitious one that attempts to overlay evidence-centered design (ECD) onto two very different kinds of assessments. As initially conceived by Mislevy, Steinberg, and Almond (1999) and their colleagues at Educational Testing Service, "The evidence-centered design (ECD) project at Educational Testing Service provides a conceptual design framework for the elements of a coherent assessment, at a level of generality that supports a broad range of assessment types, from familiar standardized tests and classroom quizzes, to coached practice systems and simulation-based assessments, to portfolios and student tutor interaction" (p. 1). The framework was designed to be (a) general enough to be applied to the myriad extant forms of assessment; (b) articulated sufficiently to be useful as a kind of development checklist against which a developer might buttress the evidentiary base of intended interpretations and uses; and (c) a mechanism for assessment improvement. The idea is not a new one, but underwritten as it was by the nation's preeminent testing organization and one of its equally preeminent psychometricians, ECD has gained considerable currency in the measurement community. The Focus article attempts to illustrate the versatility and utility of the framework by demonstrating how two very different assessments (a conventional test of mathematics-problem-solving ability using word problems and an "assessment" of conceptual physics, creativity, and conscientiousness embedded in the computer game "Newton's Playground") can both be analyzed using the processes and materials described in the framework. It is important to reiterate at the outset that ECD represents an important contribution to test development and use for two quite distinct reasons: (1) as a prospective guide to the test developer that provides a coherent and logically connected set of activities that she or he must undertake to ensure that intended interpretations and uses of an assessment under development are warranted; and (2) as a retrospective filter through which an extant assessment system can be passed for evaluative as well as improvement purposes. Whether one is applying ECD in either a prospective, developmental way or in a retrospective, evaluative way, the important point to note is that the entire effort has the effect of sensitizing the potential user to the essential interdependence of the processes and materials, and to the fact that an assessment is not simply a test and a scoring scheme. In reality, it is a coherent, articulated system of procedures and materials that when interpreted and used properly allows appropriate inferences about a person's standing on some attribute of interest. While Bond says that he applauds the effort to examine computer-based games and simulations in the context of ECD, he acknowledges that the Focus article shows that this and similar attempts in the future will not be easy.