"Fluency Formula"[TM] is a supplemental curriculum designed to promote reading fluency for first- through sixth-grade students. The program emphasizes automatic recognition of words, decoding accuracy, and oral expressiveness as the foundation for building reading fluency. A daily 10- to 15-minute lesson is delivered in the classroom. Students participate in whole-class, small-group, and individual practice activities using workbooks, read-aloud anthologies, library books, fluency activity cards, and audio CDs. The curriculum encourages at-home practice and includes a "Fluency Formula"[TM] Assessment System, which allows teachers to assess student fluency using one-minute grade-level passages and a timer. One study examined the effects of "Fluency Formula"[TM]. The study (Sivin-Kachala & Bialo, 2005) was a randomized controlled trial that met WWC evidence standards. The study began with 252 second-grade students from 12 classrooms in two suburban school districts in the Northeast. However, because the intervention targets lower-achieving students, the study authors focused only on students scoring below the 75th percentile on the Oral Fluency Assessment at pretest. The final analysis sample involved 128 students who scored below this level. The intervention group received the school's standard reading/English language arts materials and the "Fluency Formula"[TM] supplemental curriculum. The comparison group received just the school's standard reading/English language arts materials. Based on this single study, the WWC found potentially positive effects in the fluency domain and potentially negative effects in the comprehension domain. (Contains 8 footnotes.) [The following study is reviewed in this intervention report: Sivin-Kachala, J., & Bialo, E. (2005). Fluency Formula second grade study, Long Island, New York 2003-2004: Evaluation research on the effectiveness of Fluency Formula. Retrieved from Scholastic Education Web site: http://teacher.scholastic.com/products/fluencyformula/pdfs/FF_EffectivessReport.pdf.]