Contents
Purpose of the Guide to Test Interpretation............................................................ 4
Part I
Interpreting Test Results................................................................................................ 5
The Testing Program........................................................................................................... 5
Test Scores.......................................................................................................................... 5
Scale Scores.................................................................................................................. 5
Item Response Theory.................................................................................................. 6
Percentile Ranks............................................................................................................ 6
Standard Error of Measurement.................................................................................... 6
Normal Curve Equivalent............................................................................................. 7
Stanines......................................................................................................................... 7
Objective Performance Index........................................................................................ 7
Reports................................................................................................................................ 7
Home Report................................................................................................................. 8
Cal-Stik Label............................................................................................................... 10
Individual Profil Report............................................................................................... 11
Group List Report, Part I.............................................................................................. 14
Group List Report, Part II............................................................................................. 16
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Part II
Communicating Test Results....................................................................................... 17
Discussions with Students.................................................................................................. 17
After Receiving the Test Results................................................................................... 17
Discussions with Parents or Guardians............................................................................... 18
Explaining Test Results....................................................................................................... 18
How Parents or Guardians Can Help.................................................................................. 19
Purpose of the Guide to Test Interpretation
This Guide to Test Interpretation has been created to give teachers and
administrators a clear understanding of the test results for the TerraNova™,
Third Edition Complete Battery. This guide is a resource for teachers and
administrators who will be discussing test results with people who are not
acquainted with the purposes and terminology of test results.
Achievement tests serve a valuable purpose if the results are used appropriately
to support instruction in the classroom. Succeeding in this purpose begins with
understanding what the test measures and how the measurements relate to
what is being taught in the classroom.
The information in this guide explains the testing program, scores, and reports,
and how to communicate test results to students and their parents or guardians.
Copyright © 2008 by CTB/McGraw-Hill LLC
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Part I
Interpreting Test Results
The Testing Program
The TerraNova, Third Edition Complete Battery is a standardized test used
to provide consistent, accurate, and objective information about students’
achievement in various areas of the curriculum. Standard testing procedures
(with exact directions, time limits, and scoring criteria) ensure that testing
conditions are the same for all students.
When standardized tests are administered, individual or group scores may be
compared with a criterion or with the scores of other students in the class,
school, district, or national norm group. Test results can also be compared
over time intervals, which is one indication of growth for an individual or
group of students.
Test Scores
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Scale Scores
The scale score (SS) is the basic score for the TerraNova, Third Edition
Complete Battery. The scale score describes growth on a continuum of
achievement that typically occurs as a student progresses through school.
The use of a single scale for each content area across all tests and all grade
levels enables direct comparisons over time. Plotting the mean (or average)
scale scores for each grade within a school or district for successive test
administrations as well as the mean scale scores for the norm group allows
relative academic growth to be tracked, to help educational planning. However,
because the test content areas are “scaled” separately, tests in one content area
cannot be compared with tests in another. For example, a scale score of 468
on a reading test would not have the same meaning as a scale score of 468 on
a mathematics test. Converting scale scores for each content area to a normal
curve equivalent (defined on page 7) allows meaningful comparisons among
the different achievement tests.
There are two ways to derive the scale scores upon which all other
norm-referenced scores are based. The most precise method is item response
theory (IRT); the other method is number of correct responses (NCR).
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With item response theory (IRT), referred to as “IRT Pattern” scoring, the SS
is derived from not only the NCR, but also certain information about each
item. This information includes the difficulty of the item, the degree to which
it discriminates between high and low achievers, and the effect that guessing
may have on a student’s score and his or her overall pattern of responses.
IRT clearly improves the accuracy of individual examinees’ scores,
especially in the lower achievement ranges, while having little or no effect
on the average scores for classes or larger groups.
Regardless of the methodology used to derive the SS, a single set of tables
is used to determine other norm-referenced scores, including the national
percentile, the standard error of measurement, the normal curve equivalent,
and the national stanine.
Percentile Ranks
Percentile ranks, or percentiles, are commonly used for reporting results to
students and their parents or guardians. The percentiles range from 1 to 99.
The national percentile (NP) represents the percentage of students in the norm
group whose scores fall below a given student’s raw score. For example, a
student whose NP is 71 scored higher than 71 percent of the students in the
norm group.
When discussing test results with students and their parents or guardians, it is
essential to make this important distinction: A national percentile rank refers
to the percentage of students in the norm group who fall below a particular
point in the score range, not the percentage of items answered correctly. Also,
unlike most tests, in which 50 percent correct is typically considered a poor
grade, the 50th NP is the national average—the middle score—with half of the
students scoring above this percentile and half of them scoring below it.
Standard Error of Measurement
It is assumed that there is measurement error associated with any test score.
The SEM is an estimate of the amount of error expected from a particular
score for a particular test. It provides a range within which a student’s true
score is likely to fall.
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An important point to keep in mind when analyzing and interpreting scores
is that the results are only descriptions of the performance of the individual
or group on a particular test and at a particular time. From these descriptions,
inferences can be made about the abilities of the individual or group. The fact
that such inferences may not represent an individual’s true ability is taken into
account by using the standard error of measurement (SEM).
Normal Curve Equivalent
Normal curve equivalents (NCEs) are represented on a scale ranging from
1 to 99. NCEs have some of the characteristics of percentile ranks, but have
the advantage of being based on an equal-interval scale. That is, the difference
between any two successive scores on the scale has the same meaning
throughout the scale. Theoretically, because of this characteristic, a student’s
NCE on different tests can be compared. NCEs obtained by different groups of
students on the same set of tests can also be compared by averaging the scores
for the groups.
Stanines
National stanines are standard scores based on a scale of nine equal units that
range from a high of 9 to a low of 1. In general, stanines of 1 through 3 are
considered below average; stanines of 4 through 6 are considered average; and
stanines of 7 through 9 are considered above average. Since stanines are units
on an equal-interval scale, they can be readily compared. They are less precise
than a percentile rank, but are relatively easy to interpret.
Objective Performance Index
The Objective Performance Index (OPI) is reported for each content objective
measured by the test. It is an estimate of the percentage of any appropriate set
of items that a student could be expected to answer correctly. For example,
achieving an OPI of 82 on a specific objective means that if that student
were given 100 items measuring that specific objective, the student would be
expected to answer 82 of the items correctly.
Reports
Copyright © 2008 by CTB/McGraw-Hill LLC
Test results for the TerraNova, Third Edition Complete Battery are available
in computer-generated report forms. The reports are a main source of test
information and are helpful in making important decisions regarding the
instructional needs of both the class and individual students.
Guide to Test Interpretation
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The Home Report (HR) presents test information in a meaningful, easy-tounderstand way that helps parents or guardians become more involved in
their student’s education. The HR is a graph that summarizes the student’s
achievement in the content areas tested.
The scale on the left side of the graph displays the range of national
percentile scores—1 through 99—that are the basis of this report. The
student’s achievement is compared with that of the national sample of
students from which the test was “normed,” or standardized. The 50th
percentile is the national average.
2 A shaded bar displays the student’s score for each content area tested.
The height of each bar is determined by the student’s national percentile
for that content area. The actual score is also printed at the top of the bar.
3 Score ranges representing above average, average, and below average
achievement levels are shown on the right side of the graph. The gray,
shaded area—percentiles 25 through 75—indicates the average range.
4 The “Observations” section is a feature of many of the TerraNova,
Third Edition Complete Battery reports. It points out the most
significant information co veyed in the report, using some of the
student’s actual scores as examples.
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The second page of the HR—printed on the back of the report so that all the
information is on one sheet—presents detailed information about what was
measured in the specific content areas and a statement about the student’s
achievement in each content area tested. Along with information about the
student’s classroom performance, the information on the front side of the HR
can be used to focus directly on the areas of learning in which the student may
need the most help. The information on the back of the HR can then be used
for a more detailed discussion of the student’s knowledge, skills, and abilities,
and can assist in determining where to focus additional teaching.
This section gives content-based descriptions of the objectives and skills
measured in each content area assessed.
6 The statements describe how well the student performed in each content
area, in terms of content mastery.
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To help educators track student performance over time, CTB has designed
self-stick labels that provide a concise record of individual test results.
These labels can be affixed to each student’s permanent folder to provide a
yearly record of achievement. The labels show basic norm-referenced score
information for individual students, including
the student’s name and date of birth;
2 any special codes requested;
3 the year and quarter month of the norms used;
4 the scoring method used—in this case, item response theory (IRT);
5 the version, form, and level of the TerraNova, Third Edition Complete
Battery used;
6 the student’s grade level and the date of assessment; and
7 the norm-referenced scores for each test section completed.
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Individual Profile Report
The Individual Profile Report (IPR) identifies an individual student’s
strengths and needs. It uses objectives-level (criterion-referenced) scores to
help determine specific instructional priorities and norm-referenced scores
to compare achievement with the norm group. The IPR presents useful test
results clearly and understandably.
The front side, titled “Performance on Objectives,” shows the student’s
level of mastery of each objective measured by the test using the
Objective Performance Index (OPI). The OPI is an estimate of the number
of items the student could be expected to answer correctly if he
or she had completed 100 items measuring that objective.
2 The objectives measured by the TerraNova, Third Edition Complete
Battery are listed for each content area tested. Each objective is measured
by at least four items.
3 The data for each objective include
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• the student’s OPI for the objective;
• the national OPI, or the average OPI of the norm group for the
same objective;
• the difference between the student’s OPI and the national OPI—a
positive number when the student’s OPI is above the national average,
and a negative number when the student’s OPI is below
the national average; and
• the Moderate Mastery Range, which also helps define the Low
Mastery Range and the High Mastery Range.
The graph for each objective shows the student’s OPI, represented by
a small circle, and the associated confidence band, represented by a line
extending to either side of the circle. A fully darkened circle indicates
High Mastery of the objective. A half-darkened circle indicates Moderate
Mastery. An open circle indicates Low Mastery. The width of the
confidence band represents accura y—the narrower the band, the more
confidence you can h ve in the accuracy of the OPI.
The back of the IPR shows norm-referenced scores that compare the student’s
achievement with the norm group in each content area tested. This page also
shows the content measured by the test and how well the student performed.
The combination of numeric, graphic, and narrative information helps the
teacher form a well-founded general impression of the student’s level of
achievement in each content area tested.
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Guide to Test Interpretation
This section of the report displays the student’s norm-referenced scores.
The NP and the NP range are always reported. Other scores selected
by the Department of Education & Early Development are also reported.
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The graph represents the NP and the NP range, which is a confidence
band based on the SEM. The graph allows teachers or other users of the
report to make a quick assessment of the student’s relative strengths and
needs in the areas tested. The shaded area represents the range of average
scores.
7 The text below the graph presents both a summary (italicized) of a
student’s performance in a specific content area and detailed information
about what is measured in that content area. Taken together, these
statements can be used both to help the student improve and to speak
knowledgeably with parents or guardians at parent/teacher conferences.
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Group List Report, Part I
The Group List Report (GLR) provides an easy-to-understand snapshot of
the achievement of a class or other group of students. It presents important
information about norm-referenced scores, including both averages and
individual student scores.
Part I of the GLR shows average scores for the group in both tabular and
graphic formats. The user can see at a glance which content areas reflect areas
of group strength and need.
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The “Norm-Referenced Scores” section shows the number of students
with valid scores in each test section and the averages of those students
on each score requested. The second data column shows the number of
students using accommodations for each content area tested.
The key to abbreviations appears at the bottom of this score area.
The national percentile scale on the right side of the page shows the
median national percentile represented by a diamond (t ). The lines to the
left and right of the diamond represent the range between the lowest and
highest scores of the students in the group. The shaded area designates
the average range; that is, the range within which the middle half of the
national percentiles fall (NP 25 through 75).
The bottom of the graph shows the National Stanine Scale.
The “Observations” section provides specific information based on the
norm-referenced scores obtained by the group of students—a valuable
aid for understanding the data presented.
The back of Part I of the GLR is a page of key terms that defines commo
norm-referenced scores, explains how they are derived, and provides
recommendations for interpretation. The graph at the top of the page
illustrates the relationship between national stanines, national percentiles,
and normal curve equivalents.
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Group List Report, Part II
Part II of the GLR provides a permanent record of individual achievement data
for students in a class or other specified group.
Students are listed alphabetically.
8 Scores are reported for each subtest the student took.
9 Scores are provided for each section of the test completed. A total
score is also shown. (Composite scores are provided if Plus tests were
administered.)
10 All abbreviations used in the report are spelled out in this section.
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Part II
Communicating Test Results
Students and their parents or guardians can use test results to improve
the educational process. Therefore, the manner in which the test results
are communicated to them is very important. Students are likely to be
unresponsive to a teacher’s efforts to use test results to help them learn if they
have little understanding of the purpose of the test and fear how the results
may affect them. Also, parents or guardians are not likely to be supportive
of the teacher’s efforts if they sense negative reactions in their children, and
if they have inadequate or incorrect perceptions of the purposes of testing. It
is essential to communicate test results to both students and their parents or
guardians in the clearest, most positive way possible.
Discussions with Students
After Receiving the Test Results
After you have received the scoring reports, time should be set aside for you
to discuss the results with students individually. Remind your students about
the purpose of the test they have taken. Tell them that the test results are meant
to help identify knowledge and skills that they have already learned as well
as knowledge and skills they have yet to learn. Depending on the age and
maturity of the students, you may use the actual test reports in the discussion
or you may choose to discuss only portions of the test information.
Copyright © 2008 by CTB/McGraw-Hill LLC
It is not necessary to discuss test scores such as grade equivalents or scale
scores unless the student asks about them. Discussion of performance in terms
of familiar content and skills is more readily understandable and will probably
have greater meaning to the student.
To begin a discussion about test results in a positive way, point out specific
areas in which the student performed well. Then discuss content knowledge
and skills that the student needs work on. Throughout the discussion, give
the student a chance to express his or her feelings, opinions, and perceptions
about the test. The end result of this discussion should be an agreement with
the student on some instructional goals; for example, one or two skills in each
content area can be identified as needing special attention.
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Discussions with Parents or Guardians
The individual parent/teacher conference can form the basis for initiating or
continuing communication with parents or guardians about testing. Typically,
in a parent/teacher conference, all areas of a student’s school experience
are explored. As a result, the student’s performance on a particular test, and
questions about testing in general, can be put into perspective. The specific
needs of the parent/teacher conference will depend on the needs and concerns
of the individuals involved. In any discussion devoted to testing and test
results, you may want to address these three basic concerns: (1) interpretation
of the student’s test scores; (2) decisions made about the student on the basis
of these scores; and (3) the extent of parental participation in the student’s
education.
Explaining Test Results
Before talking with a parent or guardian, become thoroughly familiar with the
student’s test performance. The discussion can begin by showing the student’s
actual test report to the parent or guardian. The Home Report or the Individual
Profile Report would also be appropriate to explain. Explain test scores in
general terms, as well as how a student’s performance compares with that of
students in the norm group. Use the various norm-referenced scores, OPIs,
performance levels, and percentile ranks as references. If class or group reports
are used, all names and scores except those of the student in question should be
covered. Test information must be considered confidential.
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As you make more specific references to the strengths and needs of the
student in various content areas, use information about the test objectives
and performance level descriptions. Explain how the test results will be
used, emphasizing the positive use of test results in helping students learn.
Emphasize that the test scores represent achievement in basic skills areas at
one particular time and must be reviewed with the student’s actual classroom
work and other factors. It is important for parents or guardians to understand
that the information produced by testing is only one of the many variables that
contribute to improved learning. Parents or guardians should also understand
that the test measures the basic content and skills that are most common to
curricula throughout the country. It cannot possibly measure, nor should it
attempt to measure, the full curriculum of a particular classroom, school, or
district.
How Parents or Guardians Can Help
Schools vary considerably in the degree of parental involvement they
encourage. Parents or guardians differ, too, in the amount of time they have to
participate in school activities. All parents or guardians should be encouraged
to participate in parent/teacher conferences so they know they are an important
part of their student’s education.
Examine the individual needs of both the student and his or her parents
or guardians before you suggest ways in which parents or guardians can
help. Many parents or guardians need only to be encouraged to maintain
their present interest in their student’s performance. Others may need more
specific direction. For example, you might want to encourage some parents or
guardians to read with their student and actively converse with him or her—
two of the most important ways they can help their student learn. You might
also suggest materials or activities designed specifically to help students learn
particular skills.
Copyright © 2008 by CTB/McGraw-Hill LLC
It is important that parents or guardians feel they understand both what is
being done at school and what they can do at home. Learning about the ways
test results help students learn can contribute to that understanding.
Guide to Test Interpretation
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