Recent legislative and local school accountability efforts have placed a premium on the collection, analysis, and use of student assessment data for educational improvement. As a result, schools have sought assessments that will provide additional information about student performance. In response, a burgeoning boon industry formed—formative educational assessment systems. In this study we describe how districts search for and acquire formative assessment systems to meet their needs. We focus on three school districts that adopted three different formative assessment systems. Our findings suggest the fit between a system’s characteristics and a school district’s intended use is the most important consideration in instituting a successful formative assessment system that will have a positive impact on teacher education and student learning.