Transcript NRTs and CRTs
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