Page 63 - IJPS-8-2

International Journal of
Population Studies Projecting sex ratio at birth in Pakistan

2.2.5.2. Simulating SRB imbalance after 2020 The annual number of missing female births (AMFBs)
In provinces of Pakistan without past/ongoing SRB in province p in year t is defined as:

inflation (assessed in the model), we simulate the SRB pt, missing pt, inflationfree . The cumulative number of
pt,
imbalance process after 2020 for different starting years of
SRB inflation. missing female births (CMFB) from t to t in province p is
2
1
obtained by adding the AMFB from year t to year t :
The simulated province-specific SRB imbalance process t 2 1 2
missing
δ α is based on posterior samples in the model. The pt t , 2 pt , missing .
p
p,t
,
1
simulated δ α is added to the projected Θ for different tt 1

p
p,t
p,t
starting years of SRB inflation in each province. The
simulation process is detailed in the appendix. 3. Results
Figure 2 shows the simulated SRB imbalance process 3.1. Levels, trends, and geographic disparities in
δ α in a Pakistan province, with a given start year of provincial SRB estimates
p,t
p
the inflation process t . The SRB inflation process spans Figure 3 shows an overview of the levels and trend in
0
38 years. After approximately one decade, the imbalance provincial SRBs in Pakistan from 1980 to 2020. The median
reaches its maximum level and remains around that estimates fluctuate around the national SRB reference level
level for approximately 7 years. The SRB imbalance then (1.056) except in Balochistan and Gilgit Baltistan. In Gilgit
deflated toward the normal/reference level of SRB (i.e., the Baltistan, the SRB gradually increased from 1.058 (95%
SRB inflation becomes zero) over the next 15 years. credible interval [1.041; 1.102]) in 1980 to 1.070 [1.047;
1.125] in 2016. After reaching its provincial maximum,
2.2.5.3. Computing the number of missing female births
the SRB continuously declines. The SRB in Gilgit Baltistan
Let ψ and inflationfree denote the estimated and expected is not statistically significantly different from the national
p,t pt,
inflation-free numbers of female live births respectively, in baseline level because the 95% credible intervals overlap
province p in year t. The estimated and expected numbers with the national baseline throughout the whole period.
of female birth are calculated as ψ = B /(1+Θ ) and However, the SRB in Balochistan is an outlier from the SRBs
p,t
p,t
p,t

pt, inflationfree B pt, / pt, inflationfree , respectively. in all other provinces (Section 2.2.2 for details). The SRB
estimates from 1980 to 2020, including uncertainty for the
pt,
seven Pakistan provinces, are presented in Supplementary
The total number of births B in a given province and File 2 (https://doi.org/10.6084/m9.figshare.21548103).
p,t
year is obtained from Wazir and Goujon (2019). The Figure 4 illustrates the disparity in SRB across
number of inflation-free female births pt, inflationfree is geographic locations. The SRB is most inflated in the
obtained from the estimated number of male births southwest and northeast regions, including the Balochistan

(B − ψ ) and the inflation-free SRB inflationfree b and Gilgit Baltistan provinces.
p,t p,t pt, pt,
in the respective given province year. The number of
missing female births is calculated using a method 3.2. SRB imbalance at the provincial level
introduced in Dréze and Sen (1990), which was reviewed Table 2 lists the modeled SRB inflation probability in each
and validated in Guilmoto et al. (2020). Pakistan province. The probability of having a past or

Figure 2. SRB inflation simulation of a Pakistan province
Note: Medians are in red curve. About 95% credible intervals are in red Figure 3. Median SRB estimates in Pakistan provinces over the 1980 –
shades. t0 is the start year of the SRB inflation process. 2020 period

Volume 8 Issue 2 (2022) 57 https://doi.org/10.36922/ijps.v8i2.332