DESCRIPTION OF SURVEY POPULATION 91 are not known completely, but adjustments for deliberate exclusions, household and person listing errors, and household non- response would probably account for some share of the disagreement. A useful last step in the adjustment process would be the adjustment of survey totals to known totals by age and sex subgroups for the Nepal population. Such a procedure, known technically as poststratification, would not have been possible until population census data from 1981 became available. The effects of the compensation procedure on the age-sex population distribution are shown in Figure 3.2. The population "tree" corresponding to the base weight is contained within that cor- responding to the final adjusted weight. More "estimated persons" were added to the younger age groups than to the older, both be- cause the absenteeism and nonresponse problem was greater for younger age groups and because they are the majority of the population. Additional discussion about the population distribution by age and sex is given in Section 3.4. The findings presented in the remaining sections of this chapter and in subsequent chapters are based on weighted estimates of total population and prevalence rates. These weighted estimates thus reflect adjustments for unequal probabilities of selection as well as absenteeism and nonresponse. The basic population distributions by geographic, demographic, and environmental characteristics are given in Sections 3.3, 3.4, and 3.5, respectively. 3.3 Geographic Distributions A total of 39,887 persons, residing in 8,058 households in the final 105 survey sites, were examined in the Nepal Blindness Survey. Using the final adjusted weights described in Section 3.2, these examined persons represent an estimated 14,173,082 persons in all of Nepal, residing in 2,437,105 households. In this section the distributions of survey sites, examined persons, as well as estimated numbers of households and persons in Nepal derived from the sur- vey, are presented by several geographic characteristics for the country. The distribution by place of residence (i.e., urban or rural) is shown for sites, households, and persons in Table 3-3. Only eight of the 105 survey sites were in urban areas, locations within town panchayats, and only 6.7 percent of the 2.4 million estimated households are in urban locations as well. A slightly larger share of the 14.2 million population (7.0%) resides in urban locations reflecting somewhat larger household sizes in urban areas. Thus, the sur- vey sample results illustrate the overwhelmingly rural distribution
