<prompt> Translate the following text to EnglishUwezo wa utafiti huu ni kwamba mabadiliko ya uwezekano wa kuchanganya kama vile hali ya kijamii na kiuchumi, kazi, na uvutaji sigara haitofautiani kila siku katika eneo moja.  <response>: A particular strength of such studies is the fact that potential confounding variables such as socio-economic status, occupation, and smoking do not vary on a day-to-day basis in an individual area. 