IRS covers nearly 70 cities, 1178 towns and 2894 villages with the coverage being reviewed before the start of every round. The universe for IRS has been defined as the total resident urban and rural population of India aged 12 years and over. The survey excludes the offshore territories such as
Lakshadweep and
Andaman and Nicobar Islands. North-Eastern states (excluding
Assam) and
Jammu and Kashmir (excluding
Srinagar) are also excluded from the survey.
Sampling • The annual sample spread exceeds 2.56 lakh (256,000) respondents with continuous fieldwork spread across 10 months of the year • Sample allocated proportionate to 12 years+ Universe of a geographic unit • More than 1 Lakh towns are sampled • All publication towns and districts are sampled in the four rounds • Remaining towns and non-publication districts are randomly sampled • Rural Sampling: Once a district is selected, 2
Talukas from the district are randomly sampled
Universe projection and weightlifting • The IRS data is weighted to the
census universe • Since the Census is conducted every ten years, the estimated population for any given date is calculated by using the growth rate in between two census points. • Projection of Universe = the midpoint date of the Fieldwork period. • E.g. for FW period Jan to December the Population of India is projected to June using CDGR. (Cumulative Daily Growth Rate) Universe projections of over 1000 sub-units is accrued to arrive at the All-India Universe. • Each weighting unit is divided into a number of weighting cells to create a weighting matrix for projecting the data.
Household and individual collection • The first Household in a cluster is randomly selected based on the electoral rolls • Remaining Households selected using Right Hand Rule • Individual selection made using
Kish grid • Kish grid designed to maintain age X gender proportion in the sample. ==Significance==