<prompt> Translate the following text to EnglishKwa mfano, kwa aina tatu za kwanza za masomo ya kesi mfano, uchunguzi, na matukio muhimu generalizability, kama inahitajika, haiwezi kupatikana isipokuwa wao ni pamoja na mbinu nyingine.  <response>: That is, for the first three types of case studies illustrative, exploratory, and critical instances generalizability, if needed, cannot be achieved unless they are combined with other methods. 