DIBELS Phoneme Segmentation Fluency

Description of the PSF Measure

The DIBELS Phoneme Segmentation Fluency (PSF) measure is a standardized, individually administered test of phonological awareness (Kaminski & Good, 1996). The PSF measure assesses a student's ability to segment three- and four-phoneme words into their individual phonemes fluently. The PSF measure has been found to be a good predictor of later reading achievement (Kaminski & Good, 1996). The PSF task is administered by the examiner orally presenting words of three to four phonemes. The student then to verbally produces the individual phonemes in each word. For example, if the examiner says "sat," and the student says "/s/ /a/ /t/" he or she receives three possible points for the word. After the student responds, the examiner presents the next word, and the number of correct phonemes produced in one minute determines the final score. The PSF measure takes about 2 minutes to administer and has over 20 alternate forms for monitoring progress.

DIBELS 6th Edition Technical Adequacy of the PSF Measure

The two-week, alternate-form reliability for the PSF measure is .88 (Kaminski & Good, 1996), and the one-month, alternate-form reliability is .79 in May of kindergarten (Good, Kaminski, Shinn, Bratten, Shinn, Laimon, Smith, & Flindt, 2004). Concurrent criterion validity of PSF is .54 with the Woodcock-Johnson Psycho-Educational Battery Readiness Cluster score in spring of kindergarten (Good et al., 2004). The predictive validity of spring-of-kindergarten PSF with (a) winter-of-first-grade DIBELS NWF is .62, (b) spring-of-first-grade Woodcock-Johnson Psycho-Educational Battery Total Reading Cluster score is .68, and (c) spring-of-first-grade CBM ORF is .62 (Good et al., 2004).

How does PSF link to the Big Ideas in Beginning Reading?

PSF is a measure that assesses phonemic awareness skills.

Phonemic Awareness (PA) is:
  1. the ability to hear and manipulate the sounds in spoken words and the understanding that spoken words and syllables are made up of sequences of speech sounds (Yopp, 1992).
  2. essential to learning to read in an alphabetic writing system, because
  3. letters represent sounds or phonemes. Without phonemic awareness, phonics makes little sense.
  4. fundamental to mapping speech to print. If a child cannot hear that "man" and "moon" begin with the same sound or cannot blend the sounds /rrrrrruuuuuunnnnn/ into the word "run", he or she may have great difficulty connecting sounds with their written symbols or blending sounds to make a word.
  5. a strong predictor of children who experience early reading success.

To learn more about phonemes, phonemic awareness, and how to design and implement effective phonemic awareness instruction, visit the Big Ideas in Beginning Reading website.

PSF Sample Clip