<prompt> Translate the following text to EnglishKwa kuwa muundo wa utafiti wa kesi unazingatia kesi moja au chache na hauna udhibiti unaodhaniwa kuwa muhimu kwa uelewa wa uhusiano wa sababu, maarifa ambayo  <response>: Since case study designs center on one or a few cases and lack the controls usually thought necessary to an understanding of causal relationships, knowledge that 