<prompt> Translate the following text to EnglishKila moja ya masomo haya nested ni kutibiwa, katika suala la vipimo ya kitengo cha utafiti na ukusanyaji wa data sahihi kwa hilo, kama yoyote nyingine ya utafiti wa kesi itakuwa.  <response>: Each of these nested studies is treated, in terms of specification of the unit of study and collection of data appropriate to it, as any other case study would be. 