<prompt> Translate the following text to EnglishKwa mujibu wa utafiti wa Harvard Six Cities, kiwango cha makosa ya kipimo cha data ni cha chini kuliko kiwango cha upimaji wa kawaida EPA-SAB-COUNCIL-ADV-99-012.  <response>: The SAB has noted that the Harvard Six Cities study had better monitoring with less measurement error than did most other studies EPA-SAB-COUNCIL-ADV-99-012, 1999. 