• Demonstrating accountability.

• Making comparisons.

• Monitoring progress toward goals.

[See Program Standard A]

In addition to those purposes, assessments are conducted by school districts to make judgments about the effectiveness of specific programs, schools, and teachers and to report to taxpayers on the district's accomplishments.

The high cost of external assessments and their influence on science teaching practices demand careful planning and implementation. Well-planned, large-scale assessments include teachers during planning and implementation. In addition, all data collected are analyzed, sample sizes are well rationalized, and the sample is representative of the population of interest. This section discusses the characteristics of large-scale assessments.

Far too often, more educational data are collected than are analyzed or used to make decisions or take action. Large-scale assessment planners should be able to describe how the data they plan to collect will be used to improve science education.

[See Teaching Standard F]

The development and interpretation of externally designed assessments for monitoring the educational system should include the active participation of teachers. Teachers' experiences with students make them indispensable participants in the design, development, and interpretation of assessments prepared beyond the classroom. Their involvement helps to ensure congruence of the classroom practice of science education and external assessment practices. Whether at the district, state, or national level, teachers of science need to work with others who make contributions to the assessment process, such as educational researchers, educational measurement specialists, curriculum specialists, and educational policy analysts.

The size of the sample on which data are collected depends on the purpose of the assessment and the number of students, teachers, schools, districts, or states that the assessment plan addresses. If, for instance, a state conducts an assessment to learn about student science achievement in comparison with students in another state, it is sufficient to obtain data from a scientifically defined sample of the students in the state. If, however, the purpose of the assessment is to give state-level credit to individual students for science courses, then data must be collected for every student.

For all large-scale assessments, even those at the district level, the information should be collected in ways that minimize the time demands on individual students. For many accountability purposes, a sampling design can be employed that has different representative samples of students receiving different sets of tasks. This permits many different dimensions of the science education system to be monitored. Policy makers and taxpayers can make valid inferences about student achievement and opportunity to learn across the nation, state, or district without requiring extensive time commitments from every student in the sample.