Early in the 1970's when evaluators wanted to design studies that would capture some implementation or outcome features that were different or expensive to measure reliably on a large scale-for example, the way a large organization handled a complex innovation or the effect of an education program on motivation to learn or growth in self-confidence-they felt caught between risking considerable effort in trying to quantify qualitative variables and risking the criticism that they were ignoring really important things because they could not be measured.