- 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 off-shore territories such as Lakshadweep and Andaman & Nicobar islands, North Eastern States (except Assam) and J&K are also excluded from the survey.
- The annual sample spread exceeds 2.56 lac respondents with continuous fieldwork spread across 10 months of the year
- Sample allocated proportionate to 12 years+ Universe of a geographic unit
- All 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
- 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 Field work 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.
- 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.