Advances in computing have combined with the rapid dissemination of treatment discoveries for diseases of public health importance to create pressure for accelerated promulgation of promising research results to the medical community. The 2 recent examples of the US Carvedilol Heart Failure program and the Evaluation of Losartan In the Elderly (ELITE) study demonstrate the importance of the prospective nature of research design, as well as the consequences of its abandonment. This article explains in nonmathematical terms the rationale for the tenet "first say what you will do, then do what you said" in sample-based research.