Data on the prevalence of soil transmitted helminths (STH) and risk factors for infection (sanitation, water, hygiene) have been collected during the WASH for WORMS study, a randomized controlled trial investigating the impact of an integrated WASH and deworming intervention on STH infection in Timor-Leste. Surprisingly, analysis of the baseline data using regression models has identified few associations between STH infection and WASH variables. Surprisingly, analysis of the baseline data using regression models has identified few associations with WASH variables. Recursive partitioning approaches (classification and regression trees (C&RT) and conditional inference trees (CIT)) are alternative statistical methods that can be used to explore complex interactions between WASH variables and identify the ones most likely to be associated STH infection. The aim of this project is to use the data collected during the WASH for WORMS RCT in order to futher identify risk factors associated with worm infections.