Project Summary/Abstract Hundreds of millions of children worldwide live in poverty, and are consequently exposed to poor water and sanitation (WASH), inadequate nutrition, and insufficient caregiving. Exposure to these risk factors then causes delays in physical and mental health, and cognitive development, which can have lifelong consequences. Water, sanitation and hygiene interventions have the potential to positively affect the developmental trajectories of children by altering parental care practices and reducing enteric pathogen infection, thereby improving the quality of the environment in which young children are living. This study uses a rigorous approach – a multi-arm randomized-controlled trial (RCT) – to test the effectiveness of an innovative program promoting water, sanitation and hygiene with combined interventions to address chronic malnutrition and poor child development in Bangladesh. The scientific premise of the proposed study is strong because the intervention had consistent short-term impacts on child development outcomes across multiple domains of development (findings published in Lancet Child and Adolescent Health, 2018), and thus there is the potential that the study will also result in effects in middle childhood. The study has a high degree of scientific rigor because we use a cluster-based, randomized controlled trial (cRCT). Furthermore, we are using data with high quality measurements of child development outcomes at three time points, as well as information on maternal well-being and intervention uptake. We obtained funding for follow-up data collection, and are now seeking funding to cover personnel to analyze the existing data. The goal of the proposed study is to identify the components of an impactful early intervention that persist into mid-childhood. Our guiding hypothesis is that interventions that showed early impact will continue to have improved child outcomes at this follow-up time period. Our goals are to examine the impact of the WASH and nutrition interventions on child development and growth in children 5-8 years of age. We hypothesize that all intervention arms will show benefits to child development and growth, but that that the arms with combined treatments will have greater effects on any of the individual arms. Another goal is to examine the effects of the WASH and nutrition interventions on intermediate outcomes of caregiver mental health and caregiving practices when children are 5-8 years of age. We hypothesize that all WASH intervention arms will show benefits to caregiver mental health and caregiving practices. This proposed research is significant because it has the potential to inform interventions, programs, and policies for the hundreds of millions of children living in low-income countries. The proposed work is innovative in its examination of longer-term effects of a program, a unique combination of interventions, and high quality outcome assessments at multiple time points. The s...