Testing Terms
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Age Percentile Rank  see Percentile Rank.
Age Stanine (AS)  see Stanine.
GradeBased Norms  Developed for the purpose of comparing a student's score with the
scores obtained by other students in the same grade on the same test. How much a student
knows is determined by the student's standing or rank within the grade level score
distribution. For example, a norms table for the 6 th grade would provide information such
as the percentage of 6 th grade students (based on a nationally representative sample) who
scored at or below each obtainable score value on a particular test. Compare to AgeBased
Norms. See also: Norms, Standard Score, Grade Equivalent, and Percentile Rank.
Grade Equivalent  The grade equivalent is a number that describes a student's location on
an achievement continuum. Grade Equivalents are expressed in terms of grade and months
into grade, assuming a 10month school year (e.g., 8.4 means after 4 months of instruction in
the 8 th grade). The Grade Equivalent corresponding to a given score on any test indicates
the grade level at which the typical student obtains this score. Because of this, Grade
Equivalents are not based on an equal interval scale, and therefore cannot be added,
subtracted, or averaged across test levels the way other scores can (scale scores or standard
scores). For comparison see Age Equivalent.
Example: Standardization sample was tested in October (2 months into instruction).

Score 
Grade Equivalent 

105.0 
3.2 

108.3 
4.2 

110.6 
5.2 

112.8 
6.2 


Interpretations/Cautions of Grade Equivalent Scores:
If a sixthgrade student obtains a GE of 8.4 on the Vocabulary Test, his or her score
is like one a typical student finishing the fourth month of eighth grade would likely
get on the Vocabulary Test.
Grade Equivalents are particularly suited for estimating a student's developmental
status or yeartoyear growth. These scores are not particularly suited for identifying
a student's standing within a group or for diagnosing areas of relative strength or
weakness. Grade Equivalents do not provide a prescription for grade placement. For
example, a fourthgrade student earning a GE of 6.2 on a fourthgrade reading test
obviously demonstrates that his/her developmental level in reading is high relative to
his/her fourthgrade peers. However, the test results supply no information about
how well he/she would handle the material normally read by students in the early
months of sixth grade. It, therefore, cannot be concluded that he/she is ready for
placement in the sixth grade.
Grade Percentile Rank (GPR or PR)  see Percentile Rank.
Grade Stanine (GS)  see Stanine.
Local Norms  Norms (i.e., percentile ranks and stanines) by which test scores are referred
to a specific, limited reference population of particular interest to the test user (e.g., norms
group is based on state, district, or school data) and are not intended as representative of
populations beyond that particular setting. Used to evaluate a student's performance on a
test in comparison to other students within the same subpopulation of interest. See also:
Norms, Reference Population, Percentile Rank, and Stanine.
Local Percentile Rank  see Local Norms and Percentile Rank.
Local Stanine  see Local Norms and Stanine.
National Percentile Rank (NPR or PR) A Percentile Rank indicating the status or relative
rank of a student's score compared to a nationally representative sample of examinees. See
Percentile Rank and Norms.
National Stanine (NS or Sta9)  A stanine score indicating the status or relative rank of a
student's score compared to a nationally representative sample of examinees. See Stanine
and Norms.
Normal Curve Equivalent (NCE)  Normalized standard scores that range in value from 1
to 99, and have a mean of 50 and a standard deviation of 21.06. In order to interpret these
scores it is often necessary to relate them to other scores such as percentile ranks or
stanines. NCE's can be thought of as roughly equivalent to stanines to one decimal place.
For example, an NCE of 48 may be interpreted as a stanine of 4.8. One advantage to NCE's
is that they have the properties of an equal interval score, which means they can be
averaged, unlike Percentile Ranks. Another advantage to NCE scores is that all test
publishers derive these scores in the same way, which leads to some comparability in
reporting procedures. See also: Status Scores, Percentile Rank, Standard Score, and
Stanine.

NCEPR relationship 
NCEStanine relationship 
NCE 
PR 
NCE 
Stanine 
99 
99 
8699 
9 
90 
97 
7685 
8 
80 
92 
6675 
7 
70 
83 
5665 
6 
60 
68 
4555 
5 
50 
50 
3544 
4 
40 
32 
2534 
3 
30 
17 
1524 
2 
20 
8 
114 
1 
10 
3 


1 
1 



Normal Distribution  Also known as the bellshaped curve be cause of its distinctive
appearance in that scores are distributed symmetrically about the middle, such that there
are an equal number of scores above as below the mean, with more scores concentrated
near the middle than at the extremes. The normal distribution is a theoretical distribution
defined by specific mathematical properties that many human traits and psychological
characteristics appear to closely approximate (e.g., height, weight, intelligence, etc.). See
also: Distribution, Arithmetic Mean, Median, Mode, and Standard Deviation.
Some features of the normal distribution are:

The mean, median, and mode are identical in value.

The scores are distributed symmetrical about the mean (50.0% above the mean
and 50.0% below the mean).

68.26% of the scores are within 1 standard deviation of the mean (34.13% above
the mean and 34.13% below the mean).

95.44% of the scores are within 2 standard deviations of the mean (47.72% above
the mean and 47.72% below the mean).

99.72% of the scores are within 3 standard deviations of the mean (49.86% above
the mean and 49.86% below the mean).
Percentile  The score or point in a score distribution at or below which a given percentage
of scores fall. For example, if 72 percent of the students score at or below a score of 25 on a
given test, then the score of 25 would be considered at the 72 nd percentile. Contrast to
Percentile Rank and Percent Correct scores. See also: Distribution, Median, Quartile, and
Decile.
Percentile Band  A type of confidence interval, constructed around the examinee's obtained
Percentile Rank, indicating with a given probability or confidence, the range of scores in
which the examinee's true score may lie. Typically represented on score reports as the
shaded area or band, around the obtained Percentile Rank (signified by a diamond or other
symbol), extending from one (or more) standard error(s) of measurement below the
obtained score to one (or more) standard error(s) of measurement above the obtained score.
See also: Confidence Interval, Percentile Rank, True Score, and Standard Error of
Measurement.
Percentile Rank (PR)  The percentage of scores in a specified distribution that fall at or
below the point of a given score. Percentile Ranks range in value from 1 to 99, and indicate
the status or relative standing of an individual within a specified group (e.g., norms group),
by indicating the percent of individuals in that group who obtained lower scores. For
example, if a student earned a 72 nd Percentile Rank in Language, this would mean he or she
scored better than 72 percent of the students in a particular norm group who were
administered that same test of Language. This also implies that the only 28 percent (100 
72) of the norm group scored the same or higher than this student. Note however, an
individual's percentile rank can vary depending on which group is used to determine the
ranking. A student is simultaneously a member of many groups: classroom, grade, building,
school district, state, and nation. Test developers typically publish different sets of percentile
ranks to permit schools to make the most relevant comparisons possible. Contrast to
Percentile and Percent Correct scores. See also: Status Scores, Distribution, Norms, and
NormReferenced Interpretation.
Raw Score (RS)  The first unadjusted score obtained in scoring a test. A Raw Score is
usually determined by tallying the number of questions answered correctly or by the sum or
combination of the item scores (i.e., points). However, a raw score could also refer to any
number directly obtained by the test administration (e.g., raw score derived by formulascoring,
amount of time required to perform a task, the number of errors, etc.). In
individually administered tests, raw scores could also include points credited for items
below the basal. Raw Scores typically have little meaning by themselves. Interpretation of
Raw Scores requires additional information such as the number of items on the test, the
difficulty of the test items, normreferenced information (e.g., Percentile Ranks, Grade
Equivalents, Stanines, etc.), and/or criterionreferenced information (e.g., cut scores). See
also: Item, Item Difficulty, NormReferenced Interpretation, CriterionReference
Interpretation, Basal, Percentile Rank, Grade Equivalent, Stanine.
Scale Score (Scaled Score, SS)  A type of derived score, which is a transformation of the
raw score, developed through a process called scaling. Scale Scores provide a continuous
score scale (developmental scale) across different levels and forms of a test that permits the
direct comparison of different groups of examinees  regardless of the time of year tested
and the level/form administered (i.e., useful for longitudinal comparisons). Scale Scores,
unlike Percentile Ranks and Grade Equivalents, are equalinterval, a property that allows
these scores to be added, subtracted, and averaged. The term scale score and standard score
are often used interchangeably, even though these scores may be derived at by different
methods, their purpose and use can be similar. See also: Derived Score, Raw Score, Scaling,
Standard Score, Universal Scale Score. Contrast to Percentile Rank and Grade Equivalent.
Standard Age Scores (SAS)  Normalized standard scores, having a mean of 100 and a
standard deviation of 16, provided for each battery and composite on the Cognitive Abilities
Test (CogAT). These scores are developed for the purpose of comparing the rate and level of
cognitive development of an individual to other students in the same age group. The
Standard Age Score can be converted to other derived scores such as Age Percentile Rank
(APR) and Age Stanine (AS) through the use of a set of conversion tables. See also:
Standard Score, Norms, AgeBased Norms, Derived Score, Percentile Rank, Stanine, and
Universal Scale Score.
Standard Score (SS)  A type of derived score, which is a transformation of the raw score,
and whose score distribution in a specified population has convenient, known values for the
mean and standard deviation. Often this term is used to specifically denote zscores (mean
=0.0 and standard deviation =1.0), and any linear transformation of zscores. However,
Standard Scores can also be developed to provide a continuous score scale (developmental
scale) across different levels and forms of a test. Standard Scores permit the direct
comparison of examinees by placement of the scores on a common scale and, for this reason,
are useful for longitudinal comparisons. The term scale score and standard score are often
used interchangeably, even though these scores may be derived at by different methods,
their purpose and use can be similar. See also: Derived Score, Raw Score, Arithmetic
Mean, Standard Deviation, ZScore, Scale Score, Development Standard Score, and
Standard Age Score.
Stanine  The name stanine is simply a derivation of the term "standardnine" scale.
Stanines are normalized standard scores, ranging in value from 19, whose distribution has
a mean of 5 and a standard deviation of 2. Stanines 2 through 8, are equal to a ½ standard
deviation unit in width, with the middle stanine of 5 defined as the range of scores ¼ of a
standard deviation below to ¼ of a standard deviation above the mean. Stanines can, more
easily, be thought of as coarse groupings of percentile ranks (see below), and like percentile
ranks indicate the status or relative rank of a score within a particular group. Due to their
coarseness, stanines are less precise indicators than percentile ranks, and at times may be
misleading (e.g., similar PR's can be grouped into different stanines [e.g., PR=23 and
PR=24] and dissimilar PR's can be grouped into the same stanine [e.g., PR=24 and PR=40]).
However, some find that using stanines tends to minimize the apparent importance of minor
score fluctuations, and are often helpful in the determination of areas of strength and
weakness. See also: Standard Score, Status Scores, Percentile Rank, Arithmetic Mean, and
Standard Deviation.
Approximate
Percentile Rank
Range

Stanine 
Percent of Examinees 
Descriptor 
9699 
9 
4% 
high 
8995 
8 
7% 
well above average 
7788 
7 
12% 
above average 
6076 
6 
17% 
somewhat above average 
4159 
5 
20% 
about average 
2440 
4 
17% 
somewhat below average 
1223 
3 
12% 
below average 
511 
2 
7% 
well below average 
14 
1 
4% 
low 
Universal Scale Score (USS)  The Universal Scale Score provides a continuous growth scale
of cognitive development from kindergarten through grade 12 for the Cognitive Abilities
Test (CogAT). The USS is the standard score that is used for entry to the age and grade
norms tables to obtain such derived scores as the Standard Age Score (SAS) and the Grade
Percentile Rank (GPR) for each battery and composite score. These scores can then be
converted to other derived scores such as Age Percentile Rank (APR), Age Stanine (AS),
and Grade Stanine(GS) by the use of another set of conversion tables. See also: Scale Score,
AgeBased Norms, GradeBased Norms, Derived Score, Standard Age Score, Percentile
Rank, and Stanine.
Materials adapted from The Riverside Publishing Company's website with permission of the
publisher.
Copyright ©2002 by The Riverside Publishing Company. All rights reserved.