Chennai Mathematical Institute


National Statistics Day Symposium at Chennai Mathematical Institute
Date: 29th June 2021 (Tuesday)
Time: 9 pm - 10:30 pm (IST)
Small Area Estimation: Its Evolution in Five Decades

Malay Ghosh
University of Florida.


A "small area" or a "small domain" often refers to a small geographic area such as a county, census tract, or school district, but that need not always be the case. For instance, in a survey pertaining to a group, cross-classified by age, sex and ethnicity, even a relatively large geographical area may have very few samples. Thus a small area refers primarily to an area where the sample collected from a survey is not adequate to meet the desired precision. This unreliability of direct small area survey estimates is often due to the fact that the original survey was targeted to achieve accuracy at a higher level of aggregation. Due to limited resources, the same survey data needs to be used at a lower level, resulting in the said inadequacy of the sample size. This makes it imperative to “borrow strength” from similar other areas to increase the effecive sample size and attain the prescribed accuracy. The resulting estimates usually referred to as “indirect estimates” require explicit, or at least implicit use of models. The need for small area estimates is felt these days by both the public and private sectors. Such estimates are often mandated by the Legislature at the national and/or the state level. Small Area Income and Poverty Estimation (SAIPE) is one such example. Demand from the private sector has also increased rapidly, because business decisions, especially for small businesses, very often rely on local socio-economic conditions. My talk will be an attempt to trace the evolution of small area estimation, with a modest beginning essentially in the seventies, but with very rapid growth, especially from the nineties onwards. I will try to trace some of the salient small area estimation methods. I am, however, aware that my talk will fall short of a complete updated account as new and novel small area estimation methods are emerging every day.

Short Bio: Prof Malay Ghosh did his BSc and MSc from Calcutta University in 1962 and 1964. He was a gold medallist at both levels. He did his Ph.D. from UNC-Chapel Hill in 1969. He worked in ISI Kolkata with Prof P.C. Mahalanobish after whom National Statistics Day is being celebrated. He is an elected fellow of the Institute of Mathematical Statistics (IMS), American Statistical Association (ASA), International Society of Bayesian Analysis (ISBA). He has published more than 300 peer-reviewed articles, one edited monograph, and two books. He is a recipient of Jerzy Nayman Medal by Polish Statistical Society in 2015, the Life Time Achievement Award by the International Indian Statistical Association (IISA) in 2017, and Wilks Award of American Statistical Association in 2020.