NRTs and CRTs

Two families of tests • Norm-referenced tests (NRT) – The relative standing of a student is important (ex. TOEFL, GRE) – Students are measured against other students • Criterion-referenced (CRT) – How well a student meets a set of pre-specified criteria is important (ex. Exams in content classes) – Students are measured against a set of criterion

What do NRT scores look like?

Imagine that 24 students take a 25-item proficiency test:

Proficiency Test Results

2 1 0 7 6 5 4 3 0 4 8 12 16

Test Score

20 24 We expect most students to be “average” with some higher and some lower

NRT Humor

What do CRT scores look like?

Imagine that 24 students take a 25-item test on the first day of the semester and then again on the last day of the semester:

Pretest Results

14 12 10 8 6 4 2 0 0 4 8 12 16

Test Score

20 24

Post test Results

14 12 10 8 6 4 2 0 0 4 8 12 16

Test Score

20 24 We expect most students to “bomb” the test the first time (because they don’t know the material yet, and “ace” the test the second time (because they’ve learned the material over the course of the semester.

NRTs are good for: • Assessing general ability • Ranking and ordering students • Discriminating among students • “Gatekeeping”

Problems with NRTs • Teaching/testing mismatches • Lack of instructional sensitivity • Lack of curricular relevance • Restriction to normal distribution • Restriction to items that discriminate

CRTs are good for: • Measuring instructional gain • Determining how well students have mastered

specific

content • Studying instructional / institutional effectiveness

Comparison of NRT and CRT

Types of tests • Proficiency • Placement • Achievement • Diagnostic • Aptitude • Minimum competency