-set of abstract general concepts assembled to address a phenomena  -represent a less formal attempt than theories to explain phenomena -do not have formal propositions about relationships among phenomena
-set of abstract general concepts assembled to address a phenomena  -represent a less formal attempt than theories to explain phenomena -do not have formal propositions about relationships among phenomena
-consist of interrelated concepts -represent a less formal attempt to explain phenomena than theories  -can generate hypotheses   based on middle-range theories