This article describes the actions taken by the members of the school leadership team at McWhirter Elementary Professional Development Laboratory School in Webster, Texas, when the results of the state reading assessment in spring 2010, had taken a sudden and dramatic drop from the previous year. The team designed an action research study to examine the impact of the guided reading professional learning initiative on teacher instructional practices. The results of the exploratory action research study provided valuable insights into the dynamics surrounding student progress. During the 2011-12 school year, the team developed strategies for responding to these findings and a plan for evaluating the professional learning initiative that grew out of this process. The team viewed responses to intervention as a powerful professional learning time because it offered teachers differentiated, just-in-time learning about strategies to help students be successful.