4. Month and year of birth
All persons responding question 1 should answer this question.
Interviewers should ask and fill out the actual month and year of birth for every person based on the solar calendar. Persons who have an incorrect date of birth in their legal documents (e.g. personal identification certificate, household registration, birth certification, etc.) can report their correct date of birth in the enumeration form.
If a person does not remember her/his date of birth in the solar calendar, but s/he remembers her/his age and date of birth in the lunar calendar, interviewers can check the calendar conversion table (in the appendix) in order to get the correct year of birth in the solar calendar.
In case that a person does not remember the month of birth but s/he knows her/his age by the lunar calendar, his/her estimated year of birth is, as follow:
Year of birth (solar calendar) = year of census (1989) - age (by lunar calendar) +1
If a person does not remember the date of birth or his/her own age or that for other household members, interviewers can ask several questions to find out estimated dates of birth.
If a person cannot remember his/her age or year of birth, interviewers can look at their appearance and ask them to estimate their own ages and use the calendar conversion table to fill in the year of birth by the solar calendar.
For children, if the interviewee does not remember his date of birth, interviewers can ask months of age and calculate the month and year of birth of the child.