DSS member can be lost follow-up if the person left the DSA through non-repeatable end event type (i.e. death) or repeatable end event type (exit from DSA i.e. out-migration or exit from location). In urban slum DSS both lost follow-up as a result of out-migration or exit from residence are quite recurring phenomenon. Therefore, it is important to assess the number of people who are lost follow-up and the length of time since lost follow-up before calculating the number of person- years lived. Please consult a do-file that can be used to carry out this task. (Stata Routine for Lost to Follow up.do)