Systems analysis can play different roles in addressing problems depending on the type of problem and level of agreement. Co-learning through boundary work between science and decision-making can help address "messy" problems with many stakeholders. Effective strategies for co-learning include meaningful participation in setting the research agenda, arrangements for accountability, and producing boundary objects that can be understood from different perspectives. Challenges for systems science include meeting requirements for credible, salient and legitimate knowledge while accommodating multiple disciplines and stakeholders.