of understanding, their thinking strategies, and the nature of their misunderstandings.
During this same period, there have been significant developments in measurement methods and theory. As presented in Chapter 4, a wide array of statistical measurement methods is currently available to support the kinds of inferences that cognitive research suggests are important to draw when measuring student achievement.
In this report we describe examples of some initial and promising attempts to capitalize on these advances. However, these efforts have been limited in scale and have not yet coalesced around a set of guiding principles. In addition to discerning those principles, it is necessary to undertake more research and development to move the most promising ideas and prototypes into the varied and unpredictable learning environments found in diverse classrooms embedded within complex educational systems and policy structures.
In pursuing new forms of assessment, it is important to remember that assessment is a system composed of the three interconnected elements discussed earlier—cognition, observation, and interpretation—and that assessments function within a larger system of curriculum, instruction, and assessment. Radically changing one of these elements and not the others runs the risk of producing an incoherent system. All of the elements and how they interrelate must be considered together.
Moreover, while new forms of assessment could address some of the limitations described above and give teachers, administrators, and policy makers tools to help them improve schooling, it is important to note that tests by themselves do not improve teaching and learning, regardless of how effective they are at providing information about student competencies. Many factors affect instruction and learning, including the quality of the curriculum, the experience and skills of teachers, and the support students receive outside of class. It is also essential to keep in mind that any assessment operates within constraints, and these constraints can limit its ability to provide useful information. For example, such factors as the amount of money available for developing an assessment and the amount of instructional time available for its administration or scoring can restrict the types of tasks used for the assessment and thus the evidence it can provide about student learning. In addition, classroom factors such as class size and opportunity for teachers to interact with one another can affect teachers’ ability to profit from the information that is derived. Thus while new assessments can enhance the available information about student competencies, their full potential can be realized only by removing such constraints.
That potential is significant. Assessments that inform teachers about the nature of student learning can help them provide better feedback to students, which in turn can enhance learning (Black and Wiliam, 1998). Assess-