The research method used to evaluate a program of instruction in English as a Second Language (ESL) reading based on schema theory is discussed. The program is used in public schools in Rio de Janeiro (Brazil). In the first section, the research design, procedures, and instruments are presented. An experimental method is used, but is adapted so that ethnographic, qualitative, and process data can be used to interpret quantitative information. The rationale for this approach is discussed. In the second section, the findings of the study are analyzed. In the conclusion, an argument is made for the integration of experimental or quantitative data and ethnographic or quantitative data. This position is supported by the argument that the two kinds of data are of different natures, each with inherent limitations, and thorough research requires the use of quantitative information to clarify or question experimental findings. In this study, it is proposed that the non-experimental data were particularly helpful in calling attention to factors affecting the experiment's internal validity and in enlarging its external validity. A brief bibliography is appended. (MSE)