H.O. Hartley's Contributions to Sample Survey Theory and Methods

The late H.O. Hartley made fundamental contributions to sample survey theory and methods.In this article, an attempt is made to provide a review of his work in sampling with emphasis on ratio estimation, non-response problem, domain estimation, multiple frame surveys, unequal probability sampling, response error measurement, and foundational aspects of inference in survey sampling.The impact of his work on subsequent research in these areas is also briefly discussed.