There are different methods related to the execution of the study.
For example, if the purpose of the study is illustrative, an appropriate basis for site selection could be typical, representative, or cluster; the case studies would be conducted concurrently with other methods used in the main study; prestructuring or guidance to the evaluators in the field would be low to moderate to permit the thickness and richness of insights needed; data could be qualitative only or both qualitative and quantitative; the case studies probably would be analyzed within sites only; and the reporting would probably be narrative.