Sex ratio at birth, Tamil Nadu

Female live births per 1,000 male live births, over a three-year period.

Numerator

Female live births in the SRS sample over three years

Denominator

Male live births in the SRS sample over three years (thousands)

Methodology

The Sample Registration System (SRS) is ORGI's large-scale demographic survey: in about 8,800 randomly selected villages and urban blocks (8,839 sample units covering about 9.0 million people in 2024, roughly 0.6% of the population) a resident part-time enumerator records births and deaths continuously, and an independent supervisor conducts a retrospective half-yearly survey. The two records are matched and unmatched events re-verified in the field (dual record system), which makes SRS India's reference source for vital rates at state level, since civil registration remains incomplete in several states. The sample is redrawn after each census; the frame in use from reference year 2014 is based on Census 2011. Source: SRS Statistical Report for the reference year, Statement 16 ('Sex Ratio (female per 1000 male) at Birth by Residence'), Total column, for India and the 22 bigger States/UTs (population above 10 million at Census 2011, plus Himachal Pradesh). Each value is taken from the report for its own year, not from later reports' trend tables. IHO stores the total (rural and urban combined) for V1; SRS also publishes rural and urban figures, and for some rates figures by sex, which are not yet stored. SRS publishes the sex ratio at birth only as a three-year average (the 2024 report gives 2022–24), and IHO stores it under that three-year period. A new three-year value appears each year.

Caveats

Higher is better only up to the biological norm of about 943–952 females per 1,000 males (about 105 boys per 100 girls); a value above that is not an improvement, and in a small State it is usually sampling noise. Successive values share two of their three years, so year-on-year changes are damped. In the 2014 and 2015 reports (2012–14 and 2013–15) Andhra Pradesh's figure still included Telangana; those two values are not stored. Reference years 2020–2021 cover the COVID-19 pandemic: deaths rose sharply in 2021 (India's crude death rate was 7.5 against 6.0 in 2020), and fieldwork was disrupted.

Comparability

Not comparable with the Census child sex ratio (girls per 1,000 boys aged 0–6), which also reflects differential child mortality, or with civil registration (CRS) sex ratios, which depend on registration completeness. Jammu & Kashmir before reference year 2020 is the undivided State, which included what is now Ladakh (the 2018 and 2019 Bulletins print it as 'Jammu & Kashmir and Ladakh'); from 2020 SRS reports the Union Territories of Jammu & Kashmir and of Ladakh separately, and IHO stores both periods under Jammu and Kashmir, so its series has a boundary break at 2020. Telangana was carved out of Andhra Pradesh in 2014; SRS reports them separately from reference year 2014, so Andhra Pradesh figures are for the residuary State throughout.