This document examines contextual variables and how they affect instructional processes and educational outcomes. One contextual variable which has not received enough attention is the curriculum-material package. Curriculum packages represent potential experimental treatments. Possible research questions are whether these materials and instructions are suitable, whether they are used properly, and whether the outcomes are the ones which are expected. Once the effectiveness of a curriculum package is analyzed, the next research step is to assess the content and how it affects curriculum results. Research to date indicates that different curriculums produce different patterns of achievement and that these patterns are strongly influenced by the content emphasized in the curriculum. Further research into this area might study the influence of content, time available for instruction, student attention to task, opportunity to learn, and teacher emphasis on student achievement. (Author/DE)