This study examined science programs, instruction, and student outcomes at 30 elementary schools in a large, urban district in the northeast United States in an effort to understand whether there were meaningful differences in the quality, quantity and cost of science education when provided by a science specialist or a classroom teacher. Student performance on the state's mandated science achievement test and student engagement in science lessons were used as student outcome measures. A conceptual framework of the elementary science experience guided the study, and data were collected on all components of schools' science instruction and science programs, including their costs, through interviews, observations, surveys, and school and district records. The data suggest that there is no single answer to the question. While poorly resourced school science programs produced poor student outcomes, not all well-resourced programs produced positive student outcomes. Students in schools where there was a high school-wide value placed on science--in both science specialist and classroom teacher models--achieved the best student outcomes. Those most effective science specialist schools had significantly lower per classroom costs than the most effective schools where classroom teachers taught science; and they also had the greatest commitment to science.