Executive Summary1 Adolescents in ages 10-19 constitute one-fifth of the Indian population, and, globally, every fifth adolescent lives in India. India has articulated its commitment to protect and promote the health and rights of adolescents and meet their development needs through numerous policies and programmes, which are being implemented over the course of this century particularly. Despite these commitments, Indian adolescents and youth are, for the most part, unprepared to meet the needs of a globalising world-few complete high school, the quality of education received by many is poor, many lack livelihood skills and employment opportunities, the health of many is compromised, and gender gaps and gaps between the socio-economically disadvantaged and advantaged persist. Therefore, there is clearly a need for a commitment to ensure that promises made in policies are translated into reality for adolescents, that programmes do indeed reach adolescents, that the scope and content of the programmes are expanded, and that promising lessons are assimilated and scaled-up.Major gaps in data on adolescents pose one of the biggest challenges in promoting their rights. The absence of longitudinal data that are essential to understand the factors that determine rather than those that are associated with healthy transitions from childhood to adolescence and adulthood and successive cross-sectional data that are important to establish the levels of key markers of these transitions at various points in time have thwarted the designing of optimal programmes as well as rigorous assessment of the reach and effectiveness of on-going programmes.The programme of research titled, 'Understanding the lives of adolescents and young adults (UDAYA) in Bihar and Uttar Pradesh', implemented by the Population Council, seeks to fill these gaps in evidence. The goal of UDAYA is to establish the levels, patterns, and trends in the situation of younger (10-14) and older (15-19) adolescents and assess factors that influence the quality of transitions they make. The specific objectives of UDAYA are: (1) to explore the situation of adolescents, with a focus on assessing the extent to which both younger and older adolescents have acquired a set of assets that can help them make a healthy, safe, and successful transition from adolescence to young adulthood in the states of Bihar and Uttar Pradesh; (2) to describe the extent to which the situation of adolescents has changed over time; and (3) to assess factors that determine the accumulation or loss of assets and the quality of transitions from adolescence to young adulthood. UDAYA uses both cross-sectional and longitudinal designs and focuses on unmarried boys in ages 10-14 and 15-19, unmarried girls in ages 10-14 and 15-19, and married girls in ages 15-19 in both rural and urban settings in Bihar and Uttar Pradesh. These two states together constitute 25 percent of the country's population and adolescents in these states account for 29 percent of the country's adolescent population. This report...