ITEMS Modules

Module 1: What's the Score (Test Scores and Distributions)
• Types of tests to be discussed (standardized achievement tests, classroom tests)
• Brief overview of validity; uses and misuses of test scores
• Distributions and their properties (mean, median, mode, range, standard deviation)
• Types of scores (raw scores, percentiles, stanines, standard scores, grade-equivalents)
• Norms (importance of date and subpopulation)
• Norm-referenced and criterion-referenced score interpretation

Module 2: What Scores Do and Don't Tell Us (Imprecision in Individual and Average Test Scores)
• Measurement error (definition, sources, e.g. anxiety, inattention, timing errors)
• Reliability (definition, association with test quality and length)
• Standard error of measurement, applicability to grades, ratings etc., as well as scores
• Sampling error of means, medians, and other statistics
• Precision of individual scores versus precision of means and other summary statistics
• Implications of imprecision for interpretation

Module 3: What's the Difference (Interpretation of Test Score Differences and Trends)
• Statistical significance and how it differs from practical significance
• Implications of imprecision for interpretation of score changes and trends
• Importance of disaggregating data for key subgroups
• Effect of changes in tests and test forms; use of equating to adjust for difficulty differences
• Effects of practice, coaching, curriculum changes, and teaching to the test