Validity and Reliability

1. Reliability and validity are important to test assessment and learning because they are what keeps assessments relevant. If you do not have them then their really is not a point in taking a test that is not in a reliable and valid form.

1.1. End Note

2. Interpretation

2.1. Principles

2.2. Group variability affects the size of the reliability coefficent. Higher coefficients result from heterogeneous groups than from homogeneous groups.

2.3. Scoring reliability limits test score reliability. If tests are scored unreliabily, error is introduced that will limit the reliability of the test scores.

2.4. All other factors being equal, the more items included in a test, the higher the reliability of the scores.

2.5. Reliability of test scores tends to decrease as tests become too easy or too difficult.

3. Reliability

3.1. Is the test reliable based on the stability of test scores?

3.2. Stability

3.2.1. estimating reliability that is exactly what ts name implies...a test is given twice and the correlation between the set of scores is determined.

3.3. Equivalence

3.3.1. both forms are administered to a group of students and the correlation between the two sets of scores is determined

3.4. Internal Consistency

3.4.1. if test is designed to measure a single basic concept, it is reasonable to assume that people who get one item right will be more likely to get other and similar items also

4. Reference

5. Interpretations

5.1. Principles

5.2. Concurrent validity coefficients are generally higher than predictive validity coeffients...does not mean higher validity coefficient is more suitable for a given purpose

5.3. Group variablilty affects the size of the validity coefficient. Higher validity coefficiaent are derived from heterogeneous groups than from homogeneous groups

5.4. The relevance and reliability of the criterion should be considered in the interpretation of validity coefficients

6. Validity

6.1. Does the test measure what it is suppose to measure?

6.2. Content Validity

6.2.1. established by inspecting test questions to see whether they correspond to what the user decides should be covered by the test

6.3. Citerion-Related Validity

6.3.1. Concurrent

6.3.2. Predictive

6.4. Construct Validity

6.4.1. established when a relationship to other information corresponds well with some theory