Expeditionary Learning (EL) is a growing provider of curriculum and professional development services to teachers and school leaders. The EL model combines an interdisciplinary instructional approach with ongoing training and coaching for teachers and school leaders. The EL curriculum uses an experiential approach in which students conduct research projects to share with outside audiences. Learning expeditions--case-studies of academic topics--often bring together teachers from different subjects to coordinate shared projects; this curriculum includes several elements that are closely aligned with the Common Core standards for English-language arts and literacy. As of the 2010-2011 school year, EL's network included a total of 161 schools in 30 states. This report presents findings from the first rigorous study of the impacts of EL schools. This research aims to use the best available quasi-experimental methods to estimate the impacts of five urban EL middle schools on students' reading and math test scores. Using the study's data on student characteristics, the report also provides additional descriptive information on the types of students who enroll in EL schools. [The report was submitted to Expeditionary Learning.]