Demographic and Health Surveys Methodology - Measure DHS

Statistics: Median Age at First Sexual IntercourseDefinitionMedian age in years at first sexual intercourse.A. Coverage: Women of all marital statuses.B. Median: Interpolated calculated median.CalculationA. Age at first sexual intercourse: Reported by woman as age in completed years or when she beganliving with first husband or consensual partner. The latter response has been converted to age incompleted years in the DHS standard recode.B. Numerators: Number of women within single year of age categories. Women who never hadsexual intercourse are included in a separate category.C. Denominator is the number of women of all marital statuses. Ever-married samples denominatorsare adjusted by the all women factors.D. Numerators for each age category are divided by the same denominator and multiplied by 100 toobtain percents.E. Medians are calculated from cumulated single year percent distributions of age at first sexualintercourse. Median is linearly interpolated between the age values by which 50 percent or moreof the women had their first sexual intercourse.Handling of Missing ValuesWomen with unknown and missing ages at first sexual intercourse are excluded from both thedenominator and the numerators.Notes and ConsiderationsThe reported age at first sexual intercourse is in completed years (e.g., women reporting 19 years of age atfirst sexual intercourse actually includes all women who had their first sexual intercourse under 20 yearsof age). Therefore an adjustment is made to the interpolated median by increasing the interpolated valueby one year.Since the median is based on all women, including those who never had sexual intercourse, there may notbe a median for younger cohorts of women (since fewer than 50 percent of the cohort may have hadsexual intercourse).In most of the ever-married DHS surveys, age at first sexual intercourse was not asked. In the other evermarriedsurveys, never-married women are assumed not to have had sexual intercourse.Guide to DHS Statistics 72 Updated September 2006