19. What is the difference between internal measurement error and external measurement error? ESL

High-Quality Classroom Assessment 89 external noise factors, such as the quality of the test, scoring errors, and test direc- tions. The actual or true knowledge, reasoning, skill, or affect, the signal, is cap- tured to some extent by the assessment, but the internal and external sources of error also contribute to the score. In the end, you get an observed score that is made up of the actual or true performance plus some degree of error (noise). An important practical implication of knowing about error in testing is that small differences between scores of different students should be treated as if they were the same. Typically, your interpretation of a score of 75 should be the same as your interpretation of a score of 77. These observed scores are so close that, when we consider error that can be positive or negative, the true scores of the students should be considered equal (e.g., 75, plus or minus 3, or 77, plus or minus 3). How Is Reliability/Precision Determined for Classroom Assessments? Reliability / precision in classroom assessment is unique because teachers use results from the assessments to make instructional decisions. Thus, classroom assessment reliability / precision is a combination of measurement error, as previ- ously described, and instructional decision making (Parkes, 2013). While tradi- tional, psychometric ideas of reliability / precision focus on measurement error, in opendability of their decision