Age reporting

Digital preference

The single-year age distributions for the ash-Shati and ash-Shaja„iyya populations are plausible; there is no evidence of preference for ages ending in particular digits, for example zero or five (see Figure 4.1 and Figure 4.2).

Age transference

A second form of age misstatement is a systematic tendency for age to be under- or overstated. Age transference is potentially of greater consequence for the accurate calculation of demographic rates especially if, for example, it is associated with marital status or fertility. In closed, stable or quasi-stable populations, the systematic exaggeration or understatement of age can be easily identified by examining the population distribution by five-year age groups together with the corresponding sex ratios. In populations, which are affected by migration, the identification of errors in reported ages is more difficult. In Section 5.2 an attempt is made to establish those features of the ash-Shati and ash-Shaja„iyya population structures which arise from age and sex-selective out-migration. Even after accounting for the differential impact of emigration, evidence exists that the enumerated populations are affected by age transference. The accuracy of the demographic measures is undermined by three cases of age misstatement. These are:

 In ash-Shati there are too few women aged 20-24 and too many aged 15-19.

 Also, in the refugee camp, the ages of some of the women actually aged 40-44 are probably exaggerated. However, the number of women involved is small and certainly not large enough to reverse the relative sizes of the two age groups. (The

Figure 4.1 Age-sex distribution of the de jure 1985 survey populations of ash-Shati and ash- Shaja„iyya Ash-Shati 1985 120 100 80 60 40 20 0 20 40 60 80 100 120 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 Age Men Women Ash-Shaja‘iyya 1985 120 100 80 60 40 20 0 20 40 60 80 100 120 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 Age Men Women

111

Figure 4.2 Preference for digits in the reporting of age in the household survey measured by deviations from 10 per cent in the calculation of Myers‟ Index, ages 10-89, by sex

large number of women aged 45-49 compared with the number aged 40-44 is believed to be a genuine finding - see Section 5.2.)

 In ash-Shaja„iyya the 25-29 cohort is relatively small in comparison with the adjacent five-year age groups. The evidence indicates that the ages of some women in the latter group who have experienced higher than average fertility are recorded as 30 or 31. 4.3.2 Vital event reporting

Maternity history results

Birth histories are often subject to event displacement and omission of vital events (Potter, 1977; Goldman et al., 1979 and Balkaran, 1982). Investigation shows that, in general, the data recorded in the maternity histories are internally consistent and, compared with similar data from other Middle Eastern countries, the coverage and dating of events is good. However, there is some evidence of errors in the recording of both births and deaths.

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 9 0 1 2 3 4 5 6 7 8

Last digit of age

Males Females

Deviations from 10 per cent

Myers' summary index

Males = 4.2 Females = 4.4

Figure 4.3 Reported age-specific death rates (Mx), total population, by period

Omission of events

 The evidence suggests that women aged 45-49 in ash-Shaja„iyya failed to report some child deaths (Section 8.1).

 Figure 4.3 shows the estimated age-specific death rates for the periods 0-9, 10-19 and 20-29 years before the survey. The rates are calculated from the live births and deaths reported in the maternity histories. Compared with the level of mortality in the first month of life in the years 1975-85, the estimated neonatal mortality rate in 1965-75 is implausibly low. The same is true for the earlier period, though to a lesser extent. The most likely explanation for the anomaly is that neither the birth nor death of some infants who died at a very young age were recorded. These omissions are discussed further in the examination of sex differentials in mortality by five-year periods (Section 8.3).

Displacement of events

 The sex ratios at birth for the periods 5-9 and 10-14 years prior to the survey are 1.01 and 1.15 (Table 4.2). The sex ratios for the enumerated 5-9 and 10-14 age groups in ash-Shati are 0.99 and 1.25. Clearly both the dates of birth and the ages of some young boys in the refugee camp were incorrectly recorded. It is important to

0.000 0.001 0.010 0.100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Age in months M(x) 1955-65 1965-75 1975-85

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Table 4.2 Sex ratios at birth by current age of mothers and period before the survey (number of births in parentheses)

Current age

Years before survey

0-4 5-9 10-14 15-19 20-24 25+ All (1980-85) (1975-80) (1970-75) (1965-70) (1960-65) (Pre-1960) 15-19 90 90 (95) (95) 20-24 97 104 98 (424) (55) (479) 25-29 104 83* 210* 0 98 (390) (267) (31) (1) (689) 30-34 115 116 116 158* 117* (377) (398) (248) (31) (1054) 35-39 99 94 104 100 137 0 101 (207) (266) (286) (170) (45) (1) (975) 40-44 118 106 ₁₂₁* 108 104 124 111 (104) (171) (239) (245) (214) (65) (1008) 45-49 121 110 113 101 114 102 108 (74) (132) (243) (302) (283) (257) (1248) All 104 101 ₁₁₅* 105 112 107 106 (1598) (1289) (1047) (749) (542) (323) (5548) *

95 per cent confidence limits exclude 106.

emphasise, however, that, with this notable exception, the dating of births appears rather accurate.

 A second type of event displacement is heaping of the reported ages at death. Figure 4.3 shows the result of heaping of deaths on ages 12 and 18 months at the expense of adjacent months. As would be expected, the heaping becomes more pronounced for children born long before their mothers were interviewed. As a result of the shortage of deaths at ages 10 and 11 months and the excess of deaths at exactly one year, estimates of infant mortality in the periods 1955-65 and 1965-75 will be too low but mortality at ages 1-4 years will be over-estimated. The peaks and troughs in the monthly number of infant deaths for the two earliest periods also suggest some rounding of ages at death to 3, 6 or 9 months. In contrast, the curve of the distribution of infant deaths for children born in 1975-85 shows an almost uninterrupted progressive reduction in the number of deaths with increasing age. This is the expected pattern and the result is encouraging. The reported ages at death for children born in the period mid-1982 to mid-1985 (Figure 4.4) also reveal a plausible pattern.

Figure 4.4 Reported ages at death of children born within three years of the survey (1982-85)

It follows that estimates derived from the birth history data of recent levels of child mortality are likely to be accurate.

Comparison of household questionnaire and maternity history results

The enquiry was designed to allow the estimation of lifetime fertility from both summary questions on the household schedule and the detailed maternity histories. The total number of children ever-born reported in the household questionnaires and the number of live births recorded in the birth histories are compared in Table 4.3. The household schedule fertility questions recorded 472 (8.5 per cent) fewer births than the more detailed individual questionnaires. Other retrospective surveys which have included both sets of questions have sometimes noted an underenumeration of births when summary questions are used (see, for example, Abdel-Aziz, 1983). This is usually attributed to inaccurate proxy reporting or to the omission of children living away from home and/or children born in the distant past who have since died. The figures in the third column of Table 4.3 reveal that the proportion of births omitted increases steadily from the 20-24 group to the 40-44 group. Even for women in their twenties and early thirties, the groups for whom the level of fertility is usually the most accurately recorded, there is some underenumeration of births. In contrast to the reporting on live births, the difference in total deaths recorded

0 1 2 3 4 5 6 7 8 9 10 11 12 E L 1 2 3 6 9 12 15 18 21 24 Age - months Number of deaths E Early neonatal L Late neonatal

115

Table 4.3 Comparison of births and deaths recorded in the household questionnaires and maternity histories, by age group of mother

Births Deaths

Age group Children

ever-born HHQ (a) Live births MH (b)

(a) / (b) Dead children

HHQ (c) Live births since died MH (d) (c) / (d) 15-19 96 95 1.01 2 2 1.00 20-24 469 479 0.98 15 15 1.00 25-29 663 689 0.96 35 37 0.95 30-34 992 1054 0.94 79 78 1.01 35-39 883 975 0.91 99 98 1.01 40-44 869 1008 0.86 155 157 0.99 45-49 1104 1248 0.88 175 170 1.03 Total 5076 5548 0.91 560 557 1.01

Sources: HHQ – household questionnaires; MH - maternity histories.

is only three (0.5 per cent) and the consistency by age group is extremely good. The two causes of error cited above are therefore rejected as explanations for the anomalies in the Gaza data. The quality of the Gaza maternity history data is good; it seems that the problem is rooted in the question used to derive the number of children ever-born in the household questionnaire.

The heading of the relevant columns on the household schedule are ‘adad al-aulad al- ahya - number of children alive/living. (There was a separate column for each sex.) During the training of the interviewers it was explained that this was an abbreviation for the number of children born alive. If the missing births (and their distribution by age group) had approximated the number of deaths, it would be clear that the question was universally misunderstood to refer to children alive at the time of the survey. However, this was not the case as there are 472 missing births and 560 deaths. Examination of the numbers reported on the two schedules for ash-Shati and ash-Shaja„iyya separately (not shown) reveals the same scale of omissions. Thus, interpretation of the question did not change as the survey progressed. A simple calculation was therefore carried out to establish whether this ambiguity in the household schedule is the source of the error. For each woman, the total children „born alive‟ was calculated from both the household and the individual questionnaires. For each case in which there was not an exact match (299 cases), the number of dead children from the household schedule was added to the number „born alive‟ reported on the same questionnaire. These figures were then cross- tabulated with the total live births derived from the maternity histories. In 267 (89 per cent) of these cases the new totals agreed, indicating that the source of the error had been

correctly identified. Further investigation by sex and parity did not contradict this finding. It is therefore concluded that, when completing the questions about children ever-born on the household schedule, only one or two of the interviewers recorded the correct information, that is the number of children born alive. Most of the other interviewers consistently, but incorrectly, entered the number of living males and females in the two birth columns. Regrettably, this important error was not detected during the daily checking of the questionnaires.