Infant mortality rate, West Bengal

Deaths of children under one year of age per 1,000 live births in the period.

Numerator

Deaths under age one in the SRS sample

Denominator

Live births in the SRS sample

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 Bulletin for the reference year, Table 1 ('Estimated Birth Rate, Death Rate, Natural Growth Rate and Infant Mortality Rate'), Total column, for India and all 36 States/UTs. Each value is taken from the Bulletin for its own year; the same figure reprinted in later Statistical Report trend tables is not re-ingested, so a value changes only if ORGI re-issues that Bulletin (corrigenda are re-uploaded in place and recorded as revisions). 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. For India and the 21 bigger States/UTs the Bulletin gives a single-year IMR. For the nine smaller States (Arunachal Pradesh, Goa, Himachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, Tripura) and the Union Territories it gives a three-year pooled IMR (the 2024 Bulletin's figure covers 2022–2024), and IHO stores it under that three-year period, labelled 2022-2024, not under 2024. Each geography therefore has one kind of period throughout: annual for India and the bigger States/UTs, overlapping three-year periods for the smaller States and UTs. Where the Bulletin prints NA* (no infant death recorded in the sample), nothing is stored.

Caveats

Successive three-year values for smaller States and UTs share two of their three years, so a change between them reflects one year swapped in and one swapped out, and is damped. Even pooled, those samples record few infant deaths (Lakshadweep, Sikkim, Mizoram and Manipur values in single digits can move by several points on a handful of deaths). Manipur's 2023 and 2024 estimates are based on 130 of its 165 sample units because of the field situation in the State; they are marked low-sample. 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.