A Precise Notational System for Planning and Analysis

Writers on evaluation research have increasingly pointed to a need for greater precision, specificity and explicitness in articulating the details of research operations. A precise notational system as proposed here would be beneficial in this regard at every stage of an evaluation enterprise-in reviewing and analyzing earlier studies, in the predesign stages of evaluability assessment and formative research, in the study design and implemen tation stages, in communicating results to nonresearch personnel, and in teaching research design methods. The proposed system explicates such crucial but elusive research dis tinctions as: self-selective versus forced exposure and nonexposure, treatment stimuli versus spontaneous stimuli, randomized groups versus matched groups versus other non- randomized group comparisons, "natural" versus true experiments, laboratory versus field experiments, blackout versus treatment-control experiments, and other equally important research variations.