This document provides an overview of various research methodologies that have been used to evaluate the effectiveness of language assistance programs, including bilingual and English as a Second Language (ESL) programs. The most effective methodologies for teachers' usage include action research, case studies, and surveys. These allow teachers to directly study programs and student outcomes. Experimental designs and cross-impact analysis are better suited for larger-scale research comparisons. To develop a comparative analysis of effective Sheltered English programs, researchers might use case studies of exemplar programs, surveys of teachers, and experimental research comparing student outcomes in different program models. The document also discusses federal policies and debates around bilingual education effectiveness.