Johnston] NAVAHO POPULATION 145 



the total population of the Navaho at 81,700. Taking this estimate 

 at its face value, we can tentatively conclude that about 6 percent of 

 the Navaho population was not enrolled in 1957. The child-woman 

 ratios for the enrolled population in 1957 (table 32) suggest that this 

 deficiency is concentrated in the population under 5 years of age. 

 Such a conclusion is also supported, of course, by the high median ages 

 obtained. However, in order to bring these child-woman ratios into 

 line with the corresponding ratios obtained from other Navaho age 

 dist.ributions of this period, it would be necessary to triple the number 

 of children imder 5 that appear on the roll. Such an adjustment 

 would add about 10,000 persons to the enrolled population, giving a 

 total of about 87,000. These very crude calculations suggest that the 

 defects on this roll are not limited to a serious underregistration of 

 preschool children. Although such underregistration could easily 

 accoimt for the high median ages obtained, the excessive population 

 which would result from this adjustment suggests that the under- 

 registration of deaths among adult Navahos must also be serious. 



The remaining Navaho age medians possess the relative merit of 

 being mutually consistent. As noted previously, the number of per- 

 sons of unknown age is too small to affect the medians significantly, 

 even if all such persons are of advanced age. The relatively high 

 medians obtained from the population enrolled as of 1939 reflect the 

 apparent omission of a relatively high proportion of children. This 

 is borne out by the child- woman ratio for the 1939 enrolled population, 

 as shown in table 32 (p. 168). ^'\nien the ages (as of 1939) of persons 

 enrolled after 1939 are included, the resultant median ages decline by 

 about 1 year, on the average. The impact of these delayed enroll- 

 ments is seen more clearly in comparing the child-woman ratio in table 

 32 for the original enrolled population. This ratio rises from 456 to 

 601, indicating that nearly one-third of the children under 5 in 1939 

 were not registered on the roll at that time. The latter ratio, it should 

 be noted, still falls considerably below the corresponding ratios 

 observed among the majority of the more recent Navaho age 

 distributions. 



Furthermore, it should be observed that the medians obtained from 

 the supplementary enrolled population in 1939 are higher than those 

 obtained from most of the remaining Navaho age distributions. Per- 

 sistent underregistration of persons who were very young in 1939, com- 

 bined with underregistration of deaths occurring among older persons 

 already on the roll, undoubtedly account for this upward bias in the 

 median ages.^^ Table 28 also shows the percentage of the total popu- 



*5 The median age, like other measures of central tendency, is hardly useful as an indicator 

 of discrepancies occurrina; toward either end of an age distribution. Comparison of the 

 median ages from the original 1939 roll with those of the supplementary 1939 roll 

 furnishes a case in point. Of the 280 persons added to my sample of the original roll in 

 obtaining the supplementary roll for that year, 194, or about two-thirds were under 5 years 

 of age. Nevertheless, the resultant medians were reduced by only about 1 year. 



