This report describes a classroom artifact measure and presents early findings from an efficacy study of WestEd's Reading Apprenticeship (RA) professional development program. The professional development is designed to teach high school teachers how to integrate subject-specific literacy instruction into their regular curricula. The current RA study is notable in that it is the first to include random assignment in its design. The National Center for Research on Evaluation, Standards, and Student Testing (CRESST) designed a teacher assignment instrument to address the question of whether treatment teachers demonstrate greater integration of literacy into their instructional practice than control teachers. Early findings based on preliminary data from participating history teachers indicate that treatment teachers outperformed control teachers on 6 out of 11 rubric dimensions. These dimensions address opportunities for reading in the assignment, the strategies in place to support successful reading, teacher support for reading engagement, and student feedback. Data collection will conclude at end of the 2008-2009 school year, followed by a final report. Teacher Assignment Coversheets are appended. (Contains 1 figure and 3 tables.)