Service vs survey statistics: an evaluation of contraceptive use in Pakistan
Sultan, M.; Ali, S.M.
Pakistan Development Review 28(4 Part 2): 661-669
1989
ISSN/ISBN: 0030-9729 PMID: 12343154 Document Number: 374872
The disparities between Pakistan's survey statistics which undercount and services which overestimate contributed to the impetus to develop indirect estimates of contraceptive use in 1975 and 1984 using m values in the polynomial regression equation. In 1975, the Couple Years Protection (CYP) was used and 1985 the Component Projection Approach of the UN. The suggested improvement is the use of PGE longitudinal and Chandra and Deming method with the PFSS fertility schedule, which meets the Coale and Trussell standards (the 1975 PFS values was a near perfect fit with a mean value of 0, and the 1985 estimated schedule was mediocre and the PGE mediocre to poor.). The methodology involved comparing indirect estimates of contraceptive use with estimates from service statistics and surveys. Coale's model of marital fertility is explained with natural fertility at age (a) and the logarithmic departure from natural fertility derived from averaging empirical data. In converting the degree of deliberate marital fertility control in a population (m) as an independent variable and the scale factors indicating the level of fertility with respect to average natural fertility (M), 2 second degree polynomial regression equations were generated. The results were that in equation 1 where Y = 87.637(x) - 26.873(x)squared, the estimated use in 1975 was 20.5 with an m value of .254 compared to 5.3% reported use and 16.8% service statistics use; underreporting is apparent. Equation 2 where Y = 86.776(x)- 27.286(x)squared use is 20.3% with an m value of .254 and the increase in variance explained by .98. The contraceptive use estimate of 20% is substantiated also by Nortman (1982) and Lee and Lucas (1986), who said that a Crude Birth Rate of 40 per 1000 corresponds to a prevalence rate of around 20%. The 1985 contraceptive use value of equation 1 and 2 were 20.7 and 20.4 respectively with m values of .256.