Afghanistan Mortality Survey 2010 - Measure DHS

Figure 3.1 also shows evidence of heaping year of birth, particularly on even numbers and in theperiod 10 or more years prior to the survey. The heaping on the even years generally offsets the deficits inthe odd years and, thus, will not have a major effect on fertility trends. Notably, the results show noevidence of deliberate age displacement by the interviewer; such displacement would be expected to havetransferred births from the period 3-4 years before the survey to a point 5 years or more before the surveyin order to avoid asking the detailed questions on maternal health care that were asked for births thatoccurred in the period 0-4 years before the survey.In conclusion, some omission and displacement are inherent in the collection of retrospectivebirth history data in surveys, and there is some evidence of both problems in the AMS birth history data.However, while it is difficult to quantify omission, and, thus, assess its exact impact, the problems ofomission of female births and possibly of births in the most recent period that were detected are largelyconcentrated in the South zone and do not appear to be sufficiently large overall to seriously compromisethe estimation of the overall fertility levels. With regard to displacement, there is evidence of some ageheaping, which is expected in societies like Afghanistan where literacy is low, but no sign of deliberatetransference of children out of the most recent five-year period. Thus, displacement does not represent anissue in the analysis of fertility trends presented in this chapter.Figure 3.1 Live Births by Years Prior to the AMS 201076543210Live births (thousands) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24Years prior to survey All Afghanistan North and Central zones South zoneAMS 2010Finally, as discussed in Chapter 1, some areas in Afghanistan are not represented in the AMS2010 sample due to security reasons. The failure to cover these areas would not affect fertility estimatesfrom the survey if women in the excluded areas had on average the same fertility as the interviewedpopulation. However, because the excluded areas were predominantly rural and comparatively isolated,the presumption is that fertility is higher in those areas than in the areas covered in the survey. Thus, thesample coverage problems can be assumed to introduce a downward bias in the fertility measurespresented in this chapter. However, in reviewing results presented in this chapter, it is important torecognize that any bias introduced into the national estimates by the sample coverage problems is notlikely to be too large. For example, if the fertility rates in the excluded areas were 30 percent higher thanin the covered areas, this would raise the national rate by less than 4 percent. The situation is of courseFertility, Marriage, and Family Planning | 39