text: The ability of the case study to capitalize on insight , to shift focus as the data demand , and to let disparate pieces of evidence fall into place in ways that are not always easy to describe or command is believed to yield a richer , fuller , and truer explanation of why things look the way they do than the more limited number of tests of a priori hypotheses that other methods use .
  
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  The case study focuses on the inability to change as data changes .