During the 2004-05 school year, Parkview Elementary School experienced a dramatic shift from a focus on authentic assessment and responsive, individualized teaching to a one-size-fits-all approach to literacy assessment and instruction. In an effort to boost test scores, the district mandated the use of Open Court Reading, a scripted language arts program, and an accompanying assessment system. Our concerns led us to engage in teacher research examining this assessment system and its impact on our English Learner students. Our research raises serious questions about the value of the Open Court assessments and the larger movement they represent, with particularly detrimental effects for English Learners. Specifically, the Open Court assessment system did not provide us with the information needed to target instruction for our English learners and encouraged a style of teaching which left these students behind. Since the implementation of Open Court Reading and its assessment system, the school has seen a widening gap between the achievement of English Learners and English Only or Fluent English Proficient students. (Contains 5 figures and 1 footnote.)