Quality o f data

Despite efforts to obtain correct and reliable information, survey data are usually affected by sampling and non-sampling errors. The PCPS 1984-85 data is no exception, and is subject to errors mainly due to misreporting of ages, omissions of births and deaths, and also under-reporting of contraceptive use.

Age is a very valuable piece of information in demographic surveys and one of the main problems of surveys has been to obtain accuracy in age reporting. The demographic estimates, particularly of fertility, are generally affected by age misreporting, omission of births particularly among older women, and reference errors. In developing countries, it is common to find age misreporting when women's ages are reported in single years. The incorrect reporting of age leads to a large proportion of women falling on a particular digit and a small proportion on the neighbouring digits. Ages ending in zero and five tend to have a generally greater concentration of women while ages ending in two and eight tend to have less marked concentrations at the

expense of other digits. Such a concentration of women on a particular digit is known as age heaping (Shryock et al., 1976).

Heaping is the principal type of error in single-year age data, although single- year ages are also affected by other types of age misreporting, net underenumeration, and nonreporting or misassignment of age (Shryock et al., 1976:115). The misreporting of age is one of the common response errors encountered in censuses and surveys carried out in Pakistan (Hashmi and Alam, n.d; Nobbe and Alam, 1977; Retherford and Rele, 1989). The literacy level in the country is still low and people usually do not keep a record of their ages. Pakistan is amongst those societies where remembering the exact age of an individual is not considered important (Gray, 1987:11). Age misreporting was also found in the Pakistan Fertility Survey 1975 and other previous surveys (Yusaf, 1967; Karim and Alam, 1975). However, there has been some improvement over time in the quality of data (Booth and Shah, 1984:35).

The single-year age distribution of currently married women aged 15-49 covered in the survey is given in Figure 3.2. There is clear evidence of a preference for digits divisible by 2 and 5 for ages 15-49 years. Heaping of ages at digits ending at 'O' and '5' is particularly visible.

Whipple's index and Myer's index (Shryock et al., 1976:116-118) were also computed to test the accuracy of age reporting in this survey. Whipple's index is a very effective measure of age misstatement in terms of digit preference for 0 and 5. The index varies between 100 (representing no preference for 0 or 5) and 500 (indicating that only digits 0 and 5 were reported). Whipple's index of age preference calculated for Pakistan indicates heaping around 165 at digit 0, 178 at digit 5 and 172 on combined digits of 0 and 5. Myer's index produces an index of preferences for each terminal digit from 0 to 9 (index varying from 0 to 90 - 0, representing no heaping and 90 which would result if all ages were reported at a single digit, say 0). For Pakistan, Myer's Index calculated comes to 36.05, indicating preference for reporting ages ending with digit 0 and 5.

49, Pakistan 1984-85

0 5 -

15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

Age of women

Source: Pakistan Contraceptive Prevalence Survey 1984-85, original analysis of data.

There are also some factors that could affect responses to questions on the knowledge and the practice of family planning. Some of these factors may be cultural and others may be situational. Respondents may try to please the interviewers by giving expected answers. Alternatively, they may not report on activities which they consider private, such as the practice of family planning. In Pakistan, many women feel hesitant talking about family planning methods to strangers and avoid giving accurate responses. They may be using contraceptives, but may not like to report this to the interviewer.

It is general practice in rural areas of Pakistan that, when an interviewer comes to interview the females of reproductive age, others gather out of curiosity. The presence of the mother-in-law or the husband, particularly, cannot be avoided if they happen to be at home at the time of the interview. It is customary that a woman should not speak against the will of her husband especially when he is present. Female interviewers were instructed to try to conduct the interview in private. If they had any problem, their supervisors, who were males, helped them to solve this. However, in rural society it is

not possible to avoid this situation altogether. Therefore, the response could be biased in certain cases.

Learning from the experience of previous surveys, some of the possible sources of under-reporting in this study were reduced through pre-testing of the questionnaire, adequate training and close supervision of the interviewers. These measures, however, do not eliminate all possible sources of under-reporting. As both the interviewees and the interviewers were women, there is a chance that under-reporting of male methods has occurred. The findings show that male methods have been reported less frequently than female methods. Sultan (1987:75-76) also observed under-reporting of condom use in Pakistan.

Under-reporting of family planning methods is a usual phenomenon in a society like Pakistan, where people are hesitant to report on sensitive issues such as use of contraceptives. In the POPS 1984-85 report (Population Welfare Division, 1986), 7 per cent of cases of respondents were classified as 'suspected users' (unreported cases), based on the information that these women reported themselves as non-users, but were not pregnant, wanted no more children, had no birth in the last five years, and reported having regular menstruation. In spite of the fact that these women were exposed to risk, they did not have any births. It is possible that they had been using family planning methods to avoid pregnancies. However, the age pattem of these women indicates that most of them (78 per cent) are above 40 years of age (Table 3.2) and may thus be sub- fecund (even though they reported having regular menstruation). As such these women are not considered in this study as current users but are classified as non-users.

The results, apart from enumerator bias, response error and coverage problems, are subject to sampling errors which increase with detail of geographic and socio­ economic characteristics. However, in spite of the above shortcomings, the data collected for PCPS 1984-85 are fairly reliable because it took into consideration the shortcomings encountered in previous surveys. Furthermore, the validity of the results will not be affected much because of the relatively large sample size of the present data.

currently married non-pregnant women, Pakistan 1984-85

Age Current

users Suspectedusers

Non­ users Number of Women 15-19 1.4 0.0 98.6 454 20-24 4.4 0.1 95.5 1120 25-29 7.8 0.6 91.6 1289 30-34 12.0 2.1 86.0 953 35-39 12.4 6.7 81.0 1010 40-44 12.2 18.8 69.0 809 45-49 13.0 34.0 53.0 553 Total 9.1 7.0 83.8 6188

Source: Pakistan Contraceptive Prevalence Survey 1984-85, original analysis of data.

3.3 Demographic profile