<prompt> Translate the following text to SwahiliEvaluation case studies have covered shorter periods and involved less on-site investigation than research case studies characteristically do.  <response>: Uchunguzi wa kesi za tathmini umefunika vipindi vifupi na umehusisha uchunguzi wa chini wa mahali kuliko masomo ya kesi za utafiti kwa kawaida hufanya. 