The purpose of this study was to explore the evolution of collaborative practices of PLCs as they emerge when using technology based formative assessment via iFAIT or innovative Formative Assessment with Instruction and Technology developed by the researcher using audience response systems and the online data compiler, Eduphoria!. This study used sequential explanatory mixed methods to address the problems that schools face when implementing technology based formative assessments to improve instruction and student achievement. A survey administered in September 2012 and again in December 2012 provided a measure of teacher use of formative assessments, technology use in formative assessments, and perceptions of teachers using the PLC as a mechanism of support for technology based formative assessment. Training was facilitated by the researcher as PLCs worked together to develop, administer, and interpret formative assessments. Teacher interviews were conducted, and the study ended with the administration of the December 2012 survey and open-response questions for further qualitative analysis. Quantitative data analysis was completed using ANOVAs to determine if there were significant differences of teacher groups (subject taught, grade level taught, and years of teaching experience) use of iFAIT. This data analysis also included measures of frequency and paired sample t tests between the September and December 2012 responses. Qualitative data was analyzed using hand coding, word clouds, and WordSmith Tools. The triangulation of qualitative data in the quantitative data provided a narrative to document what collaborative factors affected the use of iFAIT. For school improvement and implementation of iFAIT, the study revealed that (1) with the right technology infrastructure, on-going professional development must be offered by administrators or sought after by teachers; (2) teachers must have strong beliefs in formative assessment and the technology that supports it; (3) open lines of communication must be supported through the PLC and administration; (4) teachers must see purpose in using revealing student data to drive instruction; and (5) PLCs must have common beliefs and believe that student achievement is connected to school improvement. PLCs should discuss data, share successes, and plan instruction through extended involvement in face-to-face and online venues as communities of practice.