Page 59 - IJPS-8-2

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

Estimating the SRB in Pakistan is challenging for two of birth records involved in the study is more than what we
reasons. First, limited data are available on birth histories reported here. The SRB observations were generated from
in the past. Without a fully developed vital registration the individual birth records in data sources with full birth
system in Pakistan, administrative birth records are histories (appendix for details of the data processing steps).
lacking, and vital events are mostly estimated based on The database is available as Supplementary File 1 (https://
household surveys. Only a few sample surveys provided doi.org/10.6084/m9.figshare.21548082).
birth histories over different periods since the 1990s. The DHS (ICF International, 2022) and Multiple
Second, the data quality of census counts is typically Indicator Cluster Survey (MICS) provide the birth histories
low because of age heaping (Feeney & Alam, 1998). In (either the full birth histories or the birth histories during
historical census data, the number of children ever born the past 24 months before the survey interview) of women
in Pakistan is either unavailable or is unreliably reported. interviewed in retrospective survey questionnaires. Birth
For example, birth histories were not collected in the records are excluded if they were born more than 20 years
1981 Pakistan census (Ali et al., 2001). Accordingly, the prior to the year in which surveys were conducted to
individual-level data of the three most recent censuses minimize recall bias from older women. Furthermore, the
in Pakistan (conducted in 1981, 1998, and 2017) contain Pakistan Social and Living Standards Measurement Survey
only the populations of boys and girls under 1 year old. (PSLM) is a provincial-level survey with high coverage
The SRB data from sample surveys such as Pakistan DHS of households in Pakistan (Pakistan Bureau of Statistics
are suffering from large uncertainties because of the small [PBS], 2019). The PSLM records births over the 12 months
sample sizes and misreporting of female births.
before the date of the survey interview. The census is
When estimating and projecting the provincial SRB in conducted once per decade and collects births in the
Pakistan, it is crucial to assess the levels and trends in the 12 months preceding the census (Minnesota Population
SRB by a reproducible statistical model. Using a Bayesian Center, 2019).
modeling approach for estimation and projection,
observations from different data sources with varying levels Given Pakistan’s lack of reliable administrative birth
of uncertainties can be synthesized and pooled together in a data, it is essential to include all available data from
systematic and reproducible fashion. The Bayesian method different surveys to produce more reliable estimates and
can take into account both provincial SRB observations projections. The practice of making use of data from
and external information on the SRB imbalance process to multiple data sources in estimation and projection has
assist in model estimation and projection. been widely used by international agencies, including the
UNICEF, UN Population Division, and the Global Burden
2. Data and methods of Disease, and researchers in global and public health to
reduce systematic bias from a single data source, to increase
2.1. Data sources the length of the period that is covered by data (Alkema
Table 1 summarizes our database of provincial SRBs et al., 2016; Bearak et al., 2018; Gerland et al., 2014; Liu &
in Pakistan, with 531 SRB observations available in Raftery, 2020; Masquelier et al., 2018; Wang et al., 2020; You
eight provinces of Pakistan. The reference years of these et al., 2015). The data sources, we used as listed in Table 1,
observations range from 1965 to 2019. The database are based on provincial representative samples. If any
contains 832,091 birth records by summing up the number future in-depth survey-specific consistency checks provide
of birth records where available. The number of birth records concrete evidence of bias in the examples of certain data
is unknown in some data series. Hence, the actual number sources, that particular data source should not be included

Table 1. Pakistan provincial SRB database

Survey Sample design Survey year # SRB observations # Births
name records
Census Census enumeration 1973, 1981, 1998 15 424,739
DHS Two-stage stratified sample design 1990 – 1991, 2006 – 2007, 2012 – 2013, 2017 – 2018, 2019 301 253,580
MICS Two-stage stratified sample design 2010, 2011, 2014, 2003 – 2004, 2007 – 2008, 2016 – 2017, 2017 – 2018 37 153,772 †
PSLM Two-stage stratified sample design 1995 – 2016, 2005 – 2006, 2007 – 2008, 2013 – 2014, 2018 – 2019 228 –
Total 531 832,091*
Note: DHS: Demographic and Health Survey; MICS: Multiple Indicator Cluster Survey; PSLM: Pakistan Social and Living Standards Measurement Survey.
† : Number of birth records available only in MICS 2017 – 2018; –: The number of birth records is unavailable; *: The total number of births obtained by
summing the available number of birth records in the 20 years before the survey conducted.

Volume 8 Issue 2 (2022) 53 https://doi.org/10.36922/ijps.v8i2.332