Careful consideration must given to the appropriateness of external and internal forms of assessments. External forms of assessment (such as standardized tests given to all students in a certain grade, or district- or state-mandated tests) rarely provide timely information for instructional decision-making. When high stakes are attached, external assessments can have an undesirable impact on decisions about content coverage and pacing (Kellaghan, Madaus, & Airasian, 1982; Archbald & Porter, 1990). For example, if tests determine grade promotion for students or if teachers receive bonuses for outstanding student achievement on tests, some educators may feel pressured to improve their students' scores on tests even if the tests do not reflect the curriculum they are teaching.
Internal forms of assessment include teacher-made tests and quizzes, assigned papers and classroom projects, and textbook chapter tests and other published materials. A great deal of assessment, however, is done informally. Teachers watch how the students react to the instructional activities in the classroom and make informal assessments based on their impressions and expectations of each student's performance. It is important for teachers to consider the quality of their informal assessment practices to ensure that these practices support learning and are not based on inaccurate teacher expectations. Instructional decisions that are based on inaccurate expectations may impede student learning.