1. CHAPTER 3: Practical Measurement Concepts
Assessing Students with Special Needs
Fifth Edition
John J. Venn
University of North Florida
© 2014, 2007, 2004 by Pearson Education, Inc. All Rights Reserved

2. Overview Basic Statistics Reliability Validity
Norm and Criterion-Referenced Assessment
Practical Measurement Concepts

3. Overview
Precisely assessing students with special needs requires knowledge of measurement concepts
Key concepts include of basic statistics, accuracy in assessment, and the effectiveness of tests and evaluation procedures

4. Basic Statistics Statistics
Summarize and give meaning to test scores and other assessment results
Distributions
Describe the pattern of test scores
Normal distributions (bell-shaped curve)

5. Basic Statistics Measures of central tendency
Describe the most frequently occurring scores
Averages
Mean, median, mode
Measures of variability
Summarize the spread or dispersion of scores
Standard deviation and standard error of measurement

6. Reliability
Accuracy and consistency of scores from tests and other other assessments
Are the scores from the test consistent?
Specific measures include test-retest, alternate-form, split-half, and interrater reliability

7. Validity Effectives of scores from tests and other assessments
Does the test measure what it is supposed to measure?
Types of validity
Content
Criterion-related
Construct
Consequences of testing

8. Norm-Referenced Assessment
Interpreting performance in relation to the performance of others
Relates individual scores to the average scores of the norm group
Norm groups are carefully selected groups of students
Places or ranks students compared with other students

9. Criterion-Referenced Assessment
Interprets performance in relation to a functional level or criterion
Closely related to instruction
Teachers use this daily in teaching lessons and monitoring student progress

10. Checklist of Practical Measurement Concepts
Applications
Checklist of Practical Measurement Concepts
Is the testing time reasonable?
Is the cost of the test reasonable?
Is the test well designed with high-quality materials?
Is the reading level of the test appropriate?
Does the test include enough items to accurately measure skills and abilities?

11. Fairness in Assessment
Equity of tests for all students
Difficult to define fairness in testing
Bias in testing
Item bias
Internal bias
External bias

12. Summary Statistics summarize and give meaning to test scores
Reliability and validity are essential technical qualities of tests and assessments
Norm and criterion-referenced assessment are two different ways to interpret performance
Fairness is the most important practical, applied consideration in assessment