Using Curriculum-Based Measurement

What is CBM?

Curriculum-based Measurement is a systematic procedure for data collection and decision making in special education (Deno, 1985). CBM is a generic way of measuring student performance using a simple set of procedures for repeated measurement of student growth. It provides information on how the student's behavior changes on a task of constant difficulty. Increase in the behavior being measured on equivalent forms of the task should represent growth. A goal is identified and then interventions are implemented to improve student performance. Weekly performance data is graphed and used by teachers to evaluate the effectiveness of their instructional interventions.

How can CBM help teach students more effectively?

CBM provides frequent and continuous feedback to the teacher about the effectiveness of his or her academic interventions with students. This feedback is used to make decisions about whether the academic intervention should be continued or changed. If the student is not making adequate progress, then instructional changes are applied to the instructional program.

How to get started using CBM?

*Reading will be used as an example following sections.

What procedure can be used for developing reading probes?

Use the following steps to develop probes to be used with the school basal series.

  1. Randomly (draw numbers from a hat) select thirty passages at each level from the district basal reading series. Divide the book into thirds, and select ten from the front, ten from the middle and ten from the back of the book. 
    Each passage should be at least 200 words in length. This is to provide enough words so the students do not finish the passage in the allotted time.
  2. Type these passages on to another sheet with the name of the passage, the reading series, and reading series level, as well as the number of the passage (1-30). This will be the student copy.
  3. Count the number of words in the passage. Note the number of words there are at the end of each line of the passage.
  4. Take the typed passage and copy it. On the copy, type the number of words there are at the end of each line. This is the teacher's copy of the probe. The numbers will help facilitate the scoring.
  5. Make a collated set of teacher copies and student copies. For example, the Holt series may have seven levels, one for each grade level, plus a preprimer. There will be two copies of each probe, one for the student (unnumbered) and one for the teacher (numbered). It is helpful to develop thirty sets of two probes at each level, of randomly selected and randomly ordered passages from the Holt series. 
    **Permission from the publisher may be needed.

What are the steps for administering reading probes?

Place the student copy (unnumbered) of the probe in front of the student. Use the teacher copy to monitor performance and mark errors.

Say to the student:
"When I say begin, start to read out loud at the top of this page. Read across the page (may need to prompt by pointing). Try to read every word. If you take too long, I will tell you the word. Be sure to try every word. Keep reading until I tell you to stop. Remember, just do the best reading that you can. Do you have any questions? Ready? Begin."

Start the stopwatch as you say "Begin."
After one minute say, "Stop. Thank you." Remove the passage.


  1. After 3 seconds of silence or hesitation, supply the word.
  2. Say nothing after incorrect words.
  3. Record errors as follows:
    1. Put a slash (/) through words read incorrectly (errors). These are recorded as errors: Mark as incorrect teacher supplied words, mispronunciations, word omissions, substitutions, and words read out of sequence.
    2. Circle unusual proper nouns (names such as Seigo) which are incorrectly read.
    3. Mark insertions with a caret (^).
  4. Self-corrections, repetitions, and dialect characteristics are NOT errors.

(If the student finishes the page before the minute is up, have her/him begin reading again from the top of the page.)

What is the procedure for scoring a reading probe?

Scoring Steps


Write the number of words the student attempted to read within the minute interval.

Billy-150 Words Attempted

Subtract the circled words (incorrectly read, unusual proper nouns) from the words read correctly. These are not counted as errors.

150 Words Read
- 2 Circled Words 
148 Total Words Read

Find the Total Words Correct (TWC) by subtracting errors from the words read.

148 Words Read
- 10 Errors 
138 Total Words Correct

Mark any insertions with ^ (caret marks). Add insertions to the errors to find the number of errors.

10 Errors
+ 2 Insertions
12 Total Errors


Billy read 138 words correctly with 12 errors. This should be written as:
138 TWC
12 Errors

Adapted from training materials used for "Data-based intervention and measurement workshop," a collaborative Project of MPS and U of M, Fall, 1990.

What are the standard practices for graphing CBM data? 

CBM graphs typically have the following parts:

Vertical Axis (ordinate) - This is for the units of measurement or indicator of student achievement (i.e. number of words read correctly per minute, number of correct letter sequences on a spelling probe, etc.).

Horizontal Axis (abscissa) - This axis represents days or dates. Typically Monday through Friday dates are listed to represent the school week. Vertical Monday lines are sometimes darker to make identification easier.

Demographic Information - This section at the top of the graph contains information about the student, including name, grade, age, teacher, target academic area, etc.

Average Achieving Peers' Median Performance - The median performance of grade level peers on the same baseline task the target student was administered.

Table for Data Record - Student probe scores are recorded in a table at the bottom of the graph.

Objective - The measurable objective is written on the graph.

Baseline - This represents initial student achievement at the beginning of the problem solving process.

Aimline - This line represents the expected rate of growth or progress for the student.

Intervention Line - A vertical line to indicate a change was made in the academic intervention.