Chapter 3 Psychometrics: Reliability & Validity

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Chapter 3 Psychometrics: Reliability & Validity 45 Measuring Learning & Performance: A Primer | Retrieved from Chapter 3 Psychometrics: Reliability & Validity The purpose of classroom assessment in a physical, virtual, or blended classroom is to measure ( , scale and classify) examinees knowledge, skills, and/or attitudes. For example in achievement testing, one measures, using points, how much knowledge a learner possesses (called scaling) and then his or her total raw point score equates to a grade, , A, B, C, etc. (called classifying). In this Chapter , we will consider essential attributes of any measuring device: Reliability and Validity .

C. Threats to and Techniques for Improving Reliability Indices 1. Threats to Reliability a. Group homogeneity: When a test is given to a very similar (homogeneous) group, the resulting scores are closely clustered and the reliability coefficient will be low. The more heterogeneous the examinee group, the higher the correlation coefficient. b.

  Reliability, Improving, Improving reliability, The reliability