Positive and negative effects of external influences on program design

Program fidelity to initial design is a critical measure in implementation research and often considered an important element of program success. This approach assumes that a program's initial design is immune to the influence of external forces and is based entirely on sound evidence, theory, and practice. Using a permanent supportive housing program for domestic violence victims as a case study, this research examines how external influences may affect program theory and design and evaluates whether such influences are perceived as opportunities or barriers by program administrators. Findings, based on document review, stakeholder interviews, and focus groups, reveal that funding and physical site characteristics, and to a lesser degree, community support and professional standards, were important external influences. Both opportunities and barriers affected program design, but these effects differed in timing and degree.