An incident response plan is a set of written instructions that outline an organization's response to network events, security incidents, and confirmed breaches. It is critical because it provides a roadmap for the incident response team to follow in the event of an incident, ensuring that the response is systematic, efficient, and effective. The inclusion of predefined communication protocols ensures that the incident response team knows whom to contact, how to report incidents, and the flow of information during a security incident. This is essential for coordinating the response efforts, managing internal and external communication, and minimizing misinformation or delays in the response.