The Pressman-Wildavsky Paradox: Four Addenda or Why Models Based on Probability Theory Can Predict Implementation Success and Suggest Useful Tactical Advice for Implementers

ABSTRACT Pressman and Wildavsky's Implementation occupies center stage in the developing literature about policy implementation, in part because of the analogy they drew between implementation processes and the multiplicative model from probability theory. This paper takes the relevance of probability theory further and considers the additive model from probability theory and conditional probabilities as well as the multiplicative model. This expanded coverage of probability theorems (1) leads to markedly increased optimism about the likelihood of successful implementation, (2) encompasses empirically reasonable tactics such as persistence, packaging of clearances, engineering bandwagons and policy reduction, and (3) generates advice to hopeful implementers – some of it non-obvious.