DIBELS First Sound Fluency (FSF)

DIBELS First Sound Fluency (FSF) is a standardized, individually administered assessment that provides a measure of phonemic awareness skills in the beginning and middle of kindergarten. FSF is available in DIBELS Next and replaces Initial Sound Fluency (ISF), an earlier measure of phonemic awareness. FSF measures how well a student can hear and produce the initial sounds in words. Each administration includes up to 30 stimulus words presented verbally by the examiner. The assessor scores each response with 2, 1, or 0 points: A correct, isolated initial sound receives 2 points, initial sounds or blends receive 1 point, and an incorrect sound receives no points. The assessor continues to present words for up to one minute, or until all 30 words have been presented. FSF is not prorated. The FSF measure takes about 2 minutes to administer and has 20 alternate forms for monitoring progress.

FSF administered is administered in Kindergarten. See the DIBELS administration timeline for complete information.

For technical information about the FSF measure see our technical reports and the National Center for Intensive Intervention.

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

FSF directly measures one of the Big Ideas in Beginning Reading: Phonological Awareness. The construct of phonological awareness includes a range of skills of varying degrees of difficulty. FSF measures a subset of these skills, that tends to be easier for younger students because there are fewer demands on working memory (i.e., students are only asked to produce the initial sound in words). As with most measures of phonemic awareness, FSF appears to work best with young students and may not be as useful for students who are already very proficient at identifying initial sounds.

To learn more, visit the Big Ideas in Beginning Reading website.