1. Assessing Student Learning
Section 4.1
Introduction to Reliability

2. Introduction to Reliability
What is reliability?

3. Introduction to Reliability
Concept: Dependability

4. Introduction to Reliability

5. Introduction to Reliability
Concept: Dependability
Calculation: Consistency

6. Introduction to Reliability
“the trustworthiness or consistency of a measure, that is, the degree to which a test or other measurement instrument… yield[s] the same results across multiple applications to the same sample…” (Zedeck, 2014, p. 307)

7. Introduction to Reliability
Reliable?
Not reliable?
Measured by degree?

8. Introduction to Reliability
Assumptions

9. Introduction to Reliability
Assumption #1
Multiple re-administrations of a test produce different results, each of which generates different estimates of [inter-item and test-retest] reliability.
0-1
TEST

10. Introduction to Reliability
Reliability Induction

11. Introduction to Reliability
Assumption #2
Reliability calculations are affected by numerous variables within the measurement process.

12. Introduction to Reliability
“[M]easurement involves much more than the test itself. The entire testing situation and the process that produces test scores must be considered. A measurement procedure… encompasses all aspects of the testing situation, such as the occasion or time of test administration,… the particular selection of test items, the modes of test administration, and the standardized conditions of testing… It includes multiple aspects of the testing process, and it is not simply limited to the test itself. All aspects of the measurement procedure may affect the consistency of scores.” (Myer, 2010, p. 10)

13. Introduction to Reliability
Assumption #3
Observed scores are indirect measures of latent ability.

14. What’s next?