Research experiences for teachers (RET) programs report benefits to teachers and students. RET programs aim to give teachers authentic science research experiences based on the premise that these experiences will improve science instruction. Specifically, many programs require teacher development of lessons and units to help translate the teachers' research experience into classroom practice. However, the design and implementation of activities incorporating proven, inquiry-based practices called for in national science education reform documents require that teachers also understand contemporary models of teaching and learning. Using a lesson plan analysis instrument producing scores found to be reliable and valid in measuring teachers' instructional approaches, we compared teacher-developed lessons from traditional RET programs with those developed in Target Inquiry, a program that supplements research experiences for teachers with a materials development experience. Traditional RET lessons scored significantly lower, suggesting that supplementing RET programs with focused materials development is valuable for promoting instructional reform. (Contains 5 tables and 3 figures.)