Evaluation Glossary


An approximation of a true score, parameter, or value. Because no instrument or statistical procedure can provide an exact (or true) score or value, essentially all data are estimates. The smaller the error of measurement, the more precise the estimate of the true score or value.


Patricia Wheeler, Geneva D. Haertel, and Michael Scriven. (1992). Teacher Evaluation Glossary, Kalamazoo, MI: The Evaluation Center, Western Michigan University.

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