1.2.1. Questions for ALL Household Members
6. and 7. Column P6 and P7: Date of birth and age
The census enumerator should devote to this part a special care, since these questions are by themselves of utmost importance, since the age variable will play a major role in the analysis of the data collected.
6. Column P6: Date of birth
The date of birth in written in Column P6 for the household members who have an official document certifying their date of birth. This date of birth will be converted into integer number of years in Column P7, as explained in the example below. For the under-five children, one shall insist to obtain the proper date of birth.
Principles for determining age from the correspondence tables:
Determining the age shall be done, whenever possible, from a birth certificate. If this is true that in urban areas most children will have a birth certificate, this is however not the case in rural areas. Indeed, the high rate of illiteracy is a major handicap for the functioning of vital registration in rural areas. Therefore, in these areas, the age is expressed as the number of rainy seasons seen by the person.
Furthermore, one should note that in rural areas, references are made to the lunar calendar, translated into vernacular languages.
This is why a correspondence table was established, in order to allow the precise determination of the date of birth for children less than 10 years of age, according to the Gregorian calendar. This technique is based on the knowledge by the respondent of three elements:
1. The number of rainy seasons lived by the child;
2. The name of the lunar month of the birth of the child;
3. The day of birth of the child in the lunar calendar.
Example: A respondent tells you that his or her child has lived 6 rainy seasons, that he or she was born on Ramadan 27. What is the exact date of birth of the child?
Response: Refer to the correspondence table provided in Annex 2. Read the intersection of line "sounkalo" and Column "6 rainy seasons". You will find that the date of birth lies between February 23, 1993 and March 23, 1993. To obtain the precise date, add 26 (that is 27 - 1) to February 23, which gives 49. Then Subtract 28, corresponding to the number of days in February, and one obtains 21. The child is therefore born on March 21, 1993. Then, one can calculate the age of the child, as if he or she had a birth certificate. If the date of enumeration is March 16, 1998, the child's age is therefore: 4 years and 11 months, or 59 months.
If the child is born on Ramadan 3, the precise date of birth will be obtained as 23+3-1 = 25, and the child's birth date would be February 25, 1993.
In general, if the result of the computation for days is higher than the number of days in the months, one shall subtract this number from the result to obtain the corresponding date.
If the first element of the calendar is known, and the two others are unknown, one could use, when needed, the approximate agricultural calendar (see Annex 3), for an estimation of the child's date of birth.