Q: What is
A: Curriculum-based measurement, or CBM, is a method of
educational progress through direct assessment of academic
skills. CBM can be used to measure basic skills in reading,
mathematics, spelling, and written expression. It can also be
used to monitor readiness skills. When using CBM, the instructor
gives the student brief, timed samples, or "probes," made up of
academic material taken from the child's school curriculum.
These CBM probes are given under standardized conditions. For
example, the instructor will read the same directions every time
that he or she gives a certain
type of CBM probe. CBM probes are timed and may last from 1 to 5
depending on the skill being measured. The child's performance
on a CBM probe is scored for speed, or fluency , and for
accuracy of performance. Since CBM probes are quick to
administer and simple to score, they can be given repeatedly
(for example, twice per week). The results are then charted to
offer the instructor a visual record of a targeted child's rate
of academic progress.
Q: What are the drawbacks
of traditional types of classroom testing?
A: Traditional academic testing methods often rely on
Norm-referenced tests are developed by testing companies to be
used in schools across the country. While these traditional
academic achievement tests can yield useful information in some
situations, they also have several significant drawbacks: Normed
to a national "average" First, to ensure that their tests can be
used by schools across the country, most testing companies set
the performance standards for their academic achievement tests
according to a national average. However, as every teacher
knows, the average
skill levels in a particular classroom or school may vary a
great deal from national averages. As a result, information from
norm-referenced tests will probably not give the instructor a
clear idea of what the typical skill-levels might be in his or
her own classroom. Lack of overlap with local, or classroom,
curriculum Also, because norm-referenced tests are designed to
measure skills across a national population, the skills that
they measure will not completely overlap those of the local
classroom curriculum. Over the course of several months, for
example, one student may gain skills in certain math computation
problems that are not measured on a particular achievement test.
The test information might then mislead a teacher into believing
that a child has made less progress than is actually the case.
Given infrequently In addition, norm-referenced tests cannot be
given very often to determine student academic progress.
Teachers who depend on these tests usually have to wait
a number of months before they can learn whether a student is
from an academic program. Less sensitive to short-term academic
Norm-referenced tests are not very sensitive to short-term gains
skills. As a result, a teacher who relies solely on these tests
to judge student growth may miss evidence of small, but
important, improvements in a child's academic functioning.
Q: What are the
advantages of CBM over other testing methods?
A: In contrast to norm-referenced academic achievement tests,
CBM offers distinct advantages. Using CBM, an instructor can
quickly determine the average academic performance of a
classroom. By comparing a given child's CBM performance in basic
skill areas to these classroom, or local, norms, the teacher can
then better judge whether that child's school-skills are
significantly delayed in relation to those of classmates.
CBM has other benefits as well:
Good overlap with curriculum - Because CBM probes are
made up of materials taken from the local curriculum, there is
an appropriate overlap between classroom instruction and the
testing materials used. In effect, CBM allows the teacher to
better test what is being taught.
Quick to administer - CBM probes are quick to administer.
For example, to obtain a single CBM reading fluency measure, the
instructor asks the student to read aloud for 3 minutes. CBM
measures in math, writing, and spelling are also quite brief.
Can be given often - CBM probes can be given repeatedly
in a short span of time. In fact, CBM probes can be given
frequently, even daily if desired. The resulting information can
then be graphed to demonstrate student progress.
Sensitive to short-term gain in academic skills - Unlike
many norm-referenced tests, CBM has been found to be sensitive
to short-term student gains. In fact, CBM is so useful a measure
of student academic progress that teachers employing it can
often determine in as short a span as several weeks whether a
student is making appropriate gains in school skills.
Q: What effect does CBM
have on academic progress?
A: Instructors are faced with a central problem: they cannot
predict with complete assurance that a particular instructional
intervention will be effective with a selected student. The
truth is that only through careful observation and data
gathering can teachers know if a child's educational program is
really effective. Much of the power of CBM, therefore, seems to
lie in its ability to predict in a short time whether an
intervention is working or needs to be altered. By monitoring
students on a regular basis using CBM the teacher can quickly
shift away from educational programming that is not found to be
sufficiently effective in increasing a child's rate of learning.
In fact, research has shown that teachers who use CBM to monitor
the effectiveness of instructional interventions tend to achieve
significantly higher rates of student learning than those
instructors who rely on more traditional test measures.
Imagine, for example, that 2 students were given the identical
program in a classroom. If the children were also monitored
using CBM reading
probes, their reading fluency could be charted over several
instructional weeks tojudge whether the reading programming was
effective. A teacher examining the graph above would have little
difficulty judging that student A had made
considerable progress in reading, whereas student B did not
fluency. The difference in progress would be so obvious that the
probably want to change student B's instructional program to
foster greater reading growth. By using CBM as a tool to track
academic progress, instructors can judge in a shorter period
whether students are learning at an optimal rate and change
their teaching approach as necessary. CBM progress-monitoring
also brings other benefits. Teachers using CBM tend to be more
realistic when estimating a student's rate of progress in the
curriculum. CBM data are also very useful for teachers when
consulting with parents, school support staff, or the Committee
on Special Education. In addition, many instructors report that
sharing CBM graphs with students can be highly motivating, as
this sharing can encourage children to try to increase their
performance from week to week.
Q: If CBM measures only
fluency, how can this approach serve as an
accurate indicator of a student's true academic abilities?
A: Fluency can be thought of as the speed with which a student
is able to produce correct answers on an academic task. In
reading, for example, fluency can be defined in concrete terms
as number of words correctly read aloud in one minute, while in
math, a fluency measure would be the number of digits correctly
computed on a worksheet in two minutes. Two major assumptions
underlie the choice of fluency as a useful measure of academic
mastery. First, children must acquire basic skills before they
can move into more challenging curriculum demands. Those
students, for example, who have not yet learned to decode words
obviously are not ready to work on advanced comprehension of
passages. As a screening instrument, CBM allows the instructor
to single out children that have failed to acquire fundamental
skills crucial to more advanced schoolwork. These children can
then be given extra instruction. Second, a student's speed, or
proficiency, in an academic skill is also of great
importance. For example, two children might be able to read an
identical passage with equal accuracy, but if one student needs
triple the amount of time required by her classmate to decode
the passage, the slower reader is going to be at a disadvantage
in the classroom. While many commercial achievement tests are
able to measure some of the skills that a child has acquired,
they typically do not measure how quickly a student can carry
out a given academic skill. In contrast, CBM gives the
instructor accurate information about the rate at which
individual children are able to complete academic tasks. CBM
also can be used to directly compare the performance of targeted
students to classroom or grade-wide norms to determine whether a
particular child is as fluent as classmates in a given
skill-area. A final argument can be offered supporting CBM (with
its emphasis on fluency) as an accurate measure of academic
achievement. Extensive research has shown that CBM can reliably
track children's academic growth. Furthermore, teachers who rely
on CBM data when evaluating the effectiveness of instructional
interventions generally have improved achievement rates in their
Q: How much instructional
time does CBM require?
A: CBM probes take only a few minutes to give to a student (with
amount of time spent depending on the basic skill that the
teacher has decided to monitor). For instance, CBM probes that
measure reading fluency are given
individually. These reading probes typically require about 5
minutes for the
instructor to give, score, and chart the results of one
measurement session. CBM probes in math, spelling, and writing
are quite time-efficient, as they can be given simultaneously to
whole groups of children. Probes in these skill areas require
from 3-5 minutes of instructional time to administer to an
entire class. In some cases, teachers have trained children to
score their own CBM probes and regularly chart their own
results, reducing the instructor's time involvement. There are
also computer software programs available that can streamline
the charting and interpreting of CBM data.
Q: What are some examples
of CBM probes?
A: Well-researched CBM procedures have been developed for
basic skills in reading, mathematics, spelling, and writing.
When using CBM to measure reading fluency, the examiner sits
individually with the child and has the student read aloud for 1
from each of 3 separate reading passages randomly chosen from a
book. During the student's reading, the examiner makes note of
decoding errors made in each passage. Then the examiner
number of words correctly read in the passage. Next, the
the word-totals correctly read for the 3 passages and chooses
the middle, or
median, score. This median score serves as the best indicator of
student's "true" reading rate in the selected reading material.
When giving CBM math probes, the examiner can choose to
administer them individually or to groups of students. There are
2 types of
CBM math probes. Single-skill worksheets contain a series of
problems, while multiple-skill worksheets contain a mix of
requiring different math operations. No matter which type of
math probe is
used, the student is given the worksheet and proceeds to
complete as many
items as possible within 2 minutes. More traditional approaches
to scoring computational math problems usually give credit for
the total number of correct answers appearing on a worksheet. In
contrast to this all-or-nothing marking system, CBM assigns
credit to each individual correct digit appearing in the
solution to a math fact. By separately scoring each digit in the
answer of a computation problem, the instructor is better able
to recognize and to give credit for a student's partial math
In spelling assessments using CBM, the instructor reads aloud
that students are to try to spell correctly within a time-limit.
may give 12 to 17 spelling words within a 2-minute period.
According to the
CBM scoring technique, spelling words are scored for correct
Correct letter-sequences are pairs of letters in a word that are
placed in the
proper sequence. Let's look at an example. The word 'talk'
contains 4 letters. However, it is considered to have 5 possible
correct-letter sequences. For each spelling word given, a
student gets credit only for those letter-pairs, or sequences,
that are written in the correct order.
CBM probes that measure writing skills are simple to administer
offer a variety of scoring options. As with math and spelling,
may be given individually or to groups of students. The examiner
lined composition sheet with a story-starter sentence at the
top. The student
thinks for 1 minute about a possible story to be written from
then spends 3 minutes writing the story. Depending on the
the teacher, the writing probe can be scored in several ways.
For example, the
instructor may decide to score the writing probe according to
the total number
of words appearing in a student's composition or for the number
Jim Wright (www.interventioncentral.org)