Evidence integration is fundamental to decision making in complex institutional settings. Many organisations still approach it as a technical process instead of an organisational capability. This publication explores evidence integration as the capability to bring diverse sources of evidence into coherent, transparent and decision-ready judgements under uncertainty. Drawing on research across complementary disciplines and observations from professional practice, it shows how institutional judgement emerges through relationships among sources, not from individual sources considered in isolation. It also demonstrates how governance and institutional design shape the evidence environments that influence future decisions. High-quality decisions depend on the ability of institutions to evaluate, reconcile and synthesise evidence in ways that are proportionate, defensible and repeatable. Strengthening evidence integration as an institutional capability can enhance governance, accountability and decision quality across public, private and research organisations.