DIBELS
- Initial Sound Fluency (ISF). ISF is the number of picture or initial sounds produced correctly and the amount of time taken to produce them. Students are presented with a page with four pictures. The child is asked to identify the picture that begins with the sound produced orally by the teacher. The teacher calculates the amount of time taken to identify the correct sound and converts the score into the number of onsets correct in a minute. Correct responses receive a score of one, whereas sounds produced incorrectly or skipped are scored as incorrect. Incorrect responses receive a score of zero.
- Letter Naming Fluency (LNF). The LNF probe is the number of letters named correctly in 1 minute. Students are presented with a page of upper- and lower-case letters arranged in a random order and are asked to name as many letters as they can. The student is allowed 1 minute to produce as many letter names as possible. Each correct letter named by the student is scored as correct. Correct responses receive a score of one, whereas letters named incorrectly or skipped are scored as incorrect. Incorrect responses receive a score of zero.
- Phonemic Segmentation Fluency (PSF). PSF is the number of phonemes produced correctly in one minute. To administer the PSF probe, the teacher orally presents words of three to four phonemes (i.e., individual sounds). For example, the examiner says “cat,” and the child says “/c/ /a/ /t/.” Points are awarded for each phoneme correctly pronounced. After the student responds, the teacher presents the next word. This process continues for 1 minute. Each correct individual sound produced by the student is scored as correct. Correct responses receive a score of one, whereas sounds produced incorrectly or omitted are scored as incorrect. Incorrect responses receive a score of zero.
- Nonsense Word Fluency (NWF). NWF is the number of letter-sounds produced correctly in one minute. The NWF probe assesses the child’s knowledge of letter-sound correspondence and blending letters into words in which letters represent their most common sounds. To administer the NWF probe, the teacher presents the student with a sheet of paper with randomly ordered vowel-consonant and vowel-consonant-vowel nonsense words (e.g., sig, rav, ov). The student is then asked to produce verbally the individual letter sound of each letter or to verbally produce the whole nonsense word. For example, if the stimulus word is “vaj” the student could say “/v/ /a/ /j/” or say the word “/vaj/” to obtain a total of three letter-sounds correct. The student is allowed 1 minute to produce as many letter-sounds or words as possible. Each correct individual sound produced by the student is scored as correct. Correct responses receive a score of one, whereas sounds produced incorrectly or omitted are scored as incorrect. Incorrect responses receive a score of zero.
- Oral Reading Fluency (ORF). ORF rate is the number of words correctly read per minute from a passage. The ORF probe assesses the child’s accuracy and fluency with connected text. To administer the ORF probe, the teacher presents the student with a reading passage of approximately 250 words. The passages are calibrated for the goal level of reading for each grade level. The student is then asked to read the passage aloud for 1 minute. Words omitted, substituted, and hesitations of more than 3 seconds are scored as errors. Words read correctly or self-corrected within 3 seconds are scored as accurate. Each correct word produced by the student receives a score of one, whereas sounds produced incorrectly or omitted are scored as incorrect. Incorrect responses are not counted in the ORF rate.
DIBELS.The Dynamic Indicators of Basic Early Literacy Skills (DIBELS) (Kaminski & Good, 1996) is an example of a derivative of CBM that uses established performance criteria to determine whether a child may be at-risk, at some risk, or at low risk for reading difficulty (typically seen in Grades K-1). Figure 4.1 highlights the established performance criteria used by the authors of the DIBELS to determine risk status.
Figure 4.1. DIBELS Quarterly Benchmarks by Grade Level
Inspection of Figure 4.1 indicates that established DIBELS performance criteria are explained for each grade level and core beginning reading skill. Moreover, these criteria are further delineated by each academic quarter of the grade level. The DIBELS performance criteria are called quarterly benchmarks and are detailed for each core beginning reading skill and grade level. For example, the criterion for oral reading fluency rate considered at low risk for reading failure is 77, 92, and 110 words read per minute by the beginning, middle, and end of third grade, respectively.
It is important to provide further details on the DIBELS, given its popularity and promise as a reading assessment tool. The DIBELS comprises a number of measures designed specifically to assess beginning reading skills of students. These measures have been found to be predictive of later reading proficiency. Tables 2.2 and 2.3 provide important information on the appropriate grade levels, types of assessments, and components of beginning reading assessed by the DIBELS. Five DIBELS assessments are used to assess beginning reading skills. Descriptions of these five assessments follow.