Design features Site selection depends on program diversity , cannot be used with highly diverse programs ; best , worst , representative , typical , or cluster bases appropriate ; must keep number of cases manageable or risk becoming minisurvey , can use survey before or after to check generalizability or mix survey with concurrent case studies selected for special purposes ; data rely on observation and structured materials , often combine qualitative and quantitative data ; analysis uses varying degrees of formalization around emergent or predetermined themes ; reports are usually thematic and describe site differences and explain these ; variation in degree of integration of data across sites and of findings from different methods
Site selection is completely arbitrary , and no information is necessary before the process is completed .