One of the most vexing methodological debates of our time (and one of the most discouraging messages for practicing evaluators) is the idea that there is a 'gold standard' evaluation design (the randomized experiment) that is generally preferable to all others. This paper discusses the history of the phased clinical trial in medicine as an example of an evolutionary lifecycle model that situates the randomized experiment within a sequence of appropriately rigorous methodologies . In addition, we propose that programs can be situated within an evolutionary lifecycle according to their phase of development. Ideally, when conducting an evaluation, the lifecycle phase of the program will be aligned with the evaluation lifecycle. This paper describes our conceptualization of program and evaluation lifecycles and their alignment. It includes a discussion of practical approaches to determining lifecycle phases, the implications of non-alignment, and how an understanding of lifecycles can aid in evaluation planning. #2011Conference #EvolutionaryLifecycle #QuantitativeMethods-TheoryandDesign