Effective communication within a project in PRINCE2 focuses on ensuring that messages are clear, consistent, and reach the right stakeholders at the right time. This involves targeting key influencers who can aid in further disseminating information throughout the project, thereby enhancing communication efficiency and effectiveness.References: = PRINCE2 7 Foundation Training Manual and official PRINCE2 website documentation

The expected success level for benefits, time, cost, quality, scope, sustainability, and risk in a project should be set by the project baseline. The baseline establishes the initial scope of what the project is expected to deliver, including standards and targets against which project performance can be measured.
PRINCE2 7 Foundation sources on project planning and control.

Effective issue and change control within a PRINCE2 project relies heavily on a configuration management system. This system tracks all items of the project, including their versions and changes, allowing for controlled changes and ensuring that all items are identified, accounted for, and monitored throughout the project. References: PRINCE2 Foundation official study guide and online resources.

The 'Manage by Stages' principle in PRINCE2 allows the project board to control the project effectively by reviewing its viability at the end of each management stage. This review process provides regular control points where the continuation of the project is assessed based on its performance and continued business justification. References: PRINCE27 Foundation Handbook and official training materials.