In Research Through Design and Transdisciplinarity, Alain Findeli and his colleagues (Swiss Design Network conference 2008) interestingly propose a tentative framework for Design Research.

Their typology of design research practices goes like this:

"Research for design is highly relevant for design practice, since its purpose is to make sure that the various parameters on which the output of the design process depends (technological, ergonomic, economic, aesthetic, psychological, etc.) are adequately handled, i. e. that the design project is properly and responsibly informed.

Research about design is normally performed by various disciplines, other than design, according to scientific standards. (...) The problem we encounter with this kind of research is its relative lack of relevance for design. By “design” is here meant design practice, design education or design research. Why is that so? Well, because the research is carried out about design (i.e. about its objects, its processes, its actors and stakeholders, its meaning and significance for society, business, culture, etc.) by scientists (like anthropologists, archaeologists, historians, cognitive psychologists, management scientists, semioticists and many others) whose main goal is to contribute to the advancement of their own discipline, not particularly of design.

Research through Design: a kind of re- search about design [more] relevant for design, or as a kind of research for design that produces original knowledge with as rigorous [and demanding] standards as research about design. (...) we call this approach project-grounded research "

Why do I blog this? framing my course about field research for design leads me to this sort of theoretical categories.