Demographic and Health Surveys Methodology - Measure DHS

AgeTotal ChildrenTotal ChildrenSmoothedCurrentBreastfeedingSmoothed139.9147.5113.065.116.8....Proportion StillBreastfeeding0–12–34–56–78–9...34–35166.3223.2291.3219.6234.4...118.5166.3226.9244.7248.4223.1...118.584.165.046.226.27.5....Median 4.1To smooth the distribution by a three-group moving average, take the previous, current, and followingvalue of the distribution and divide it by 3. For example, the smoothed total children for the age group 2–3 comes from: (166.3 + 223.2 + 291.3)/3. The first (0–1) and last (34–35) age groups cannot be smoothed,so they remain with the original values. The number of children currently being breastfed is shown afterthe data were smoothed. With the distributions smoothed, the percentages of children in each group arecalculated.The first age (duration) for which the proportion falls below 50 percent will be used for the calculation ofthe median by linear interpolation between the midpoint of that age group and the next youngest midpointage. The median in this example falls between the age groups 2–3 and 4–5. Between these two age groupsis when the transition from more than 50 percent (65.0%) to less than 50 percent (46.2%) of children stillbeing breastfed occurred. The interpolation is then done between the midpoints for the age groups, whichare 2.5 and 4.5.The reason for taking the midpoint is that age is calculated by subtracting the date of birth of the childfrom the date of the interview. As a result, kids reported to be age x are in fact between exact ages x andx+1. A reasonable assumption is that these kids are on the average age x. A category consisting ofreported ages x to x+1 has a midpoint at exact age (x+x+1)/2.It should be noted that the midpoint for the first age group is calculated in a somewhat different manner.On the average, there are only about half as many children born in the month of the interview than in anyother regular month. A reasonable age for children born in the month of interview is 0.25, assuming thatinterviews are uniformly distributed. Thus, the age average for kids born 0 to 1 months is calculated as(0.5 * 0.25 + 1)/1.5 = 0.75.All Women FactorsDefinitionFactors for adjusting ever-married samples to estimate statistics based on all women are as follows.A. Coverage: All women factors are specific for individual years of age and specific for theparticular subgroup to be estimated (e.g., there are two sets of factors by type of area: one forurban areas and one for rural areas).B. Numerator: Number of all de facto womenC. Denominator: Number of de facto ever-married women.Guide to DHS Statistics 18 September 2003