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Differences between CRTs and NRTs
Many educators and members of the public fail to grasp the distinctions between criterion-
referenced and norm-referenced testing. It is common to hear the two types of testing referred
to as if they serve the same purposes, or shared the same characteristics. Much confusion can
be eliminated if the basic differences are understood.
The following is adapted from: Popham, J. W. (1975). Educational evaluation. Englewood Cliffs,
New Jersey: Prentice-Hall, Inc.
CRTs versus NRTs
Dimension Criterion-Referenced Tests Norm-Referenced Tests
Purpose A grade-level was not
identified To determine
whether each student has
achieved specific skills or
concepts.
To find out how much students
know before instruction begins
and after it has finished.
To rank each student with
respect to the achievement of
others in broad areas of
knowledge.
To discriminate between high
and low achievers.
Content
Measures specific skills which
make up a designated
curriculum. These skills are
identified by teachers and
curriculum experts.
Each skill is expressed as an
instructional objective.
Measures broad skill areas
sampled from a variety of
textbooks, syllabi, and the
judgments of curriculum
experts.
Item Characteristics
Each skill is tested by at least
four items in order to obtain an
adequate sample of student
performance and to minimize
the effect of guessing.
The items which test any given
skill are parallel in difficulty.
Each skill is usually tested by
less than four items.
Items vary in difficulty.
Items are selected that
discriminate between high and
low achievers.
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Dimension Criterion-Referenced Tests Norm-Referenced Tests
Score Interpretation
Each individual is compared
with a preset standard for
acceptable achievement. The
performance of other
examinees is irrelevant.
A student’s score is usually
expressed as a percentage.
Student achievement is
reported for individual skills.
Each individual is compared with
other examinees and assigned a
score–usually expressed as a
percentile, a grade equivalent
score, or a stanine.
Student achievement is
reported for broad skill areas,
although some norm-referenced
tests do report student
achievement for individual skills.
