A communication matrix is a tool that helps you identify and organize your communication needs and activities for a project. It typically consists of four columns: stakeholder, message, channel, and frequency. Stakeholder refers to the person or group that you need to communicate with, such as your sponsor, team, client, or vendor. Message refers to the key information or update that you need to deliver, such as project scope, status, risks, or changes. Channel refers to the medium or format that you will use to communicate, such as email, phone, report, or presentation. Frequency refers to how often you will communicate, such as daily, weekly, monthly, or as needed.