<prompt> Translate the following text to SwahiliThe second was in the combination of case study methods with other methods, particularly surveys, in order to achieve the generalizability that evaluators called external validity.  <response>: Kama ilivyoelezwa hapo juu, mfano wa utafiti wa kesi ni mchanganyiko wa njia za utafiti wa kesi na mbinu nyingine, hasa uchunguzi, ili kufikia generalizability ambayo watathmini waliita uhalali wa nje. 