This action research study investigated how formative data use influences teaching and learning, and what impact the formative process has on student outcomes. The study took place in a first-grade classroom with a group of five students over the course of four weeks. Participants were selected for the study because they scored in the 2nd to 11th percentile rank on the FastBridge Early Reading English assessment. Quantitative data was collected weekly for each of the four weeks using FastBridge Word Segmenting progress monitoring and then compared to baseline data taken before the study. A one-way between subjects ANOVA test was used to compare FastBridge Word Segmenting progress monitoring mean scores. Findings indicate a statistically significant difference between groups. The researcher concludes formative data use does influence teaching and learning as evidenced by positive student outcomes.