The Longitudinal Ageing Study in India (LASI): Research and sampling design dynamics
Jul 26, 15:20
Background: The Longitudinal Ageing Study in India (LASI) main wave 1 (2017-18) is a national landmark in scientific research that allows a better understanding of India’s adult and elderly health problems and population ageing processes and aims to inform in the design of appropriate evidence-based policies for adults and older people in India. Under the aegis of Ministry of Health and Family welfare (MoHFW), Government of India, LASI is implemented by International Institute for Population Sciences(IIPS), Mumbai, in collaboration with Harvard School of Public Health (HSPH) and the University of Southern California(USC), USA.
Design, coverage and objectives: LASI is world’s largest biennial longitudinal ageing study both in size and subject scope and India’s first. The long-term goal of LASI is to continue for the next 25 years. LASI data is collected based on internationally comparable research design, survey schedules and gold standard survey protocols. and adopts cutting edge scientific methods and state of the art survey technology and innovations. LASI covers all 30 states and 6 union territories of India with a panel sample size of 61,000 older adults aged 45 years and above. The target sample for LASI is community-dwelling (non-institutionalized) Indian residents aged 45 and older, and their spouses regardless of age.
The main goal of LASI is to collect credible scientific data on burden of disease, functional health, health care, health care financing and social and economic wellbeing of older adults. LASI implements three survey schedules namely: a household survey, an individual survey and a community survey and a comprehensive biomarkers module.
Sampling design: LASI adopts longitudinal multi-stage cluster panel sampling design. The main design characteristics included 1) three state stratification: a) state rural-urban stratification b) within state regional stratification with add on implicit SES stratification and c) PSU (sub-district) level rural-urban stratification and; 2) three-stage sample selection in rural area and four-stage sample selection in urban areas for each state and union territories. In each state, at first stage, involved selection of Primary Sampling Units (PSUs-sub-districtsTehsils/Talukas); the second stage involved the selection of villages from rural areas and ward from urban areas of the selected PSUs. In rural areas, at the third stage, households are selected from selected villages. However, sampling in urban areas involves one more stage. From each selected urban ward, one Census Enumeration Block(CEB) is randomly selected in the third stage. At the fourth stage, households from this CEB will be selected.