Description

AGEAT1STBIRTH (V212) reports the age of the woman at the time of her first birth. This variable is calculated by using the century month code (CMC) of the date of the woman's first birth (DOB1STKIDCMC) and the CMC of the woman's date of birth (DOBCMC).

Century month codes (CMC) are particularly useful for checking the consistency of dates, calculating intervals between events, and imputing dates when the information for an event is missing or partially complete.

Century month codes (CMC) are calculated by multiplying by 12 the difference between the year of an event and 1900. The year 1900 was chosen as the reference period because all of the DHS-relevant events occurred during the twentieth or twenty-first centuries. The month of the event is added to the previous result.

For example, the CMC for June 2002 is:

In other words, 1,230 months have elapsed between January 1900 and June 2002. Starting with CMC figures, one can calculate the month and year using the following formulas:

For more information, visit The DHS Program website to find the latest Guide to DHS Statistics.

Comparability

Apart from universe differences, AGEAT1STBIRTH (V212) is largely comparable across samples. Very young ages (e.g., under age 10) appearing as values in some samples may reflect rounding down (say, to a number ending in 5 or 0) of reported current age by some respondents.

Comparability - Standard DHS

AGEAT1STBIRTH (V212) is a standard recode variable that is included and consistent across all phases of the standard DHS questionnaire.

Universe