This article reviews practice variation in the field of instructional design. First, it compares instructional designer practice as reported or observed in several classic research studies. This analysis is framed by the standards established by the International Board for Training, Performance, and Instruction competencies for planning and analysis, design and development, implementation, and management. Although no certain causal linkages exist, we briefly review some of the reasons posited in the literature to explain instructional design practice variation (lack of time and resources, control in decision making, the designer's perception of a task, underlying philosophical beliefs, and designer expertise). Limitations of the literature base are explored, followed by a proposal for an alternative view of instructional design practice variation and recommendations. (Contains 6 tables.)