Demographic and Health Surveys Methodology - Measure DHS

AGE AT FIRST BIRTHStatistics: Percent Distribution by Years of Age at First BirthDefinitionPercentages of women who had a first birth in the specified age groups.A. Coverage: Women of all marital statuses.B. Numerator: Number of women whose first birth occurred in the time they were in the specifiedage group.C. Denominator: Total number of women including those without a birth.CalculationA. Age at first birth: Difference between birth date of first-born child and birth date of woman (inCMC format) grouped into categories of age in years.B. Numerators: Number of women within specified age group categories. Women with no births areincluded in a separate category.C. Denominator is the number of women of all marital statuses. Ever-married sample denominatorsare adjusted by the all women factors.D. Numerators for each age group category are divided by the same denominator and multiplied by100 to obtain percentages.Handling of Missing ValuesNot applicable—Birth dates of children and women are imputed if missing; therefore birth dates do nothave missing values.Notes and Considerations1. Percentages add up to 100 percent.2. Percentages are not calculated for the first-birth age categories by cohorts of women wherethe youngest member of the cohort has not yet completed the oldest age of the category. (Forexample, percentages for the cohort of women 20–24 at the time of the survey will not becalculated for age group categories 20–21, 22–24, and 25+ because some women withoutbirths are still in or below those age ranges and could still have first births within the agegroup categories).Guide to DHS Statistics 38 Updated September 2006