Survey methodology for the assessment of disease burden of leprosy in India

Estimation of leprosy by conventional sampling requires a large sample size. In addition, there is a likelihood of not getting even a single event after covering a large sample in conventional sampling methodology. In such a situation, inverse sampling procedure could be a choice. During 2009, inverse sampling for estimation of disease burden was tested on pilot basis in one district namely; Bareilly of Uttar Pradesh State, India, with an aim to evolve inverse sampling and validity of inverse sampling vis-à-vis conventional sampling. The pilot study found that inverse sampling is feasible in terms of cost and time and could be adopted at country level. Accordingly, a national level study using inverse sampling with modifications was designed by the National Institute of Medical Statistics during the year 2010. This paper presents the detailed methodology of the inverse sampling for estimation of disease burden of leprosy at national level with a view that the same could be applied in other similar situations.