Fragmented welfare service delivery has been identified as a significant barrier to improving outcomes for highly disadvantaged populations. The YP4 trial, conducted from 2005 to 2009, sought to evaluate, by randomised control method, an approach proposed by Campbell et al. (2003) for integrating delivery of employment, housing, health and other services for young homeless jobseekers. Rather than providing extra access to services or utilisation of different services, the YP4 trial involved assignment of a case manager to tailor and coordinate available services to reflect the specific circumstances of young homeless jobseekers. We find that the YP4 program did not have a significant effect on economic or psychological well‐being, a finding that is robust to application of experimental and quasi‐experimental methods. It is argued that our study contributes to knowledge on programme design, particularly in relation to the importance of the scale of intervention and programme administration.