Kingdon's streams metaphor describes how problems, policies, and politics interact in the policymaking process. The problem stream involves attributes and perceptions of issues, the policy stream comprises potential solutions, and the politics stream concerns public opinion and priorities. Windows of opportunity for policy change open when these three streams converge, such as when a focusing event draws attention to a problem or understanding of an issue evolves. While the streams model provides insight, critics argue it does not fully account for the ongoing policy process after a window opens.