Reliability of Assessment

Chapter 3- Reliability of Assessment

Vocabulary:

1.- Reliability: The consistency with which a test measures whatever it’s measuring: Reliability = Consistency.

2.- The Standards for Educational and Psychological Testing (AERA, 1999): A joint publication of the American Educational Research Association, the American Psychological Association, and the National Council on Measurement in Education ( the most important document governing educational assessment procedures).

3.- Types of reliability evidence:

a) Stability (Test- Retest)- Consistency of results among different testing occasions. It is a form of reliability, refers to consistency of test results over time.

Correlation Coefficient- It is computed between students’ test scores on two assessment occasions that is the initial test and the retest. It reflects the degree of similarity between students’ scores on the two tests. It is a numerical indicator (ranging from +1.0 to -1.00). A correlation coefficient (r) near 1 indicates a strong relationship. A correlation coefficient near 0 indicates a weak relationship.

b) Alternate Form- Consistency of results among two or more different forms of a test.

c) Internal Consistency- Consistency in the way an assessment instrument’s items function.

4.- Classification Consistency: Approach to the determination of a test’s stability reliability that might be used.

5.- Kuder-Richardson procedure (K-R formulae): Most commonly used internal consistency approach for tests containing items on which students can be right or wrong.

6.- Cronbach’s coefficient alpha : Most commonly used internal consistency approach for tests containing items on which students can be given different numbers of points, such as essay items.

7.- Standard error of measurement (SEM): The index used in educational assessment to describe the consistency of a particular person’s performance(s)

Chapter 4: Validity

1. Validity: It is the most important concept in assessment. Validity hinges on the accuracy of our inferences about students’ status with respect to a curricular aim. Tests, themselves, do not possess validity; it is inaccurate to talk about “the validity of a test”.

2. Curricular aim: Skill or body of knowledge that students are supposed to learn. It also referred as a content standard.

Classrooms assessments, if they are truly going to help teachers to make solid instructional decisions, should allow teachers to arrive at valid inferences (interpretations) about students.

3. Accuracy of an Assessment Inference: It is the overall