1. survey
A survey is a retrospective study of a situation to try to document relationships and outcomes. A survey is always done after an event has occurred. When performing a suvey, you have no control over the situation at hand. That is, because it is a retrospective study, you can record a situation and compare it with similar ones. But you cannot manipulate variables as you do with case studies and experiments. Surveys try to poll what is happening broadly over large groups of projects: "research in the large" [Fenton&Pfleeger 1996].