2.1 Principles of effective response

The core principles of IMS are:

  • communication
  • coordination
  • collaboration
  • flexibility

IMS helps incident responders work together to achieve common objectives. By using IMS, responders can adapt to the specific needs of an incident through the use of common roles, responsibilities and structures. This section explains the importance of the principles of effective response.

All core principles of IMS are equally important. Effective communication provides shared situational awareness and protects responders and the public. Coordination helps incident responders from different communities and organizations achieve common objectives under a shared governance system. Collaboration fosters an environment to help incident responders work well together. Flexibility allows communities and organizations to use only the resources and tools necessary to achieve common objectives.

This section also outlines the specific tools that support the core principles of IMS.

2.2 Communication

Clear communication throughout an incident is essential. Failures in communication undermine the overall response effort and can endanger incident responders and the general public.

During incidents, the demand for information can be overwhelming. IMS provides guidance on effective communication during an incident. Aspects of communication that IMS provides guidance on includes:

  • information management, which involves public information management and internal information management
  • telecommunications technology and systems management

Information management

There are two types of incident information that need to be managed:

  • public information
  • internal information

Public information

It is critical to share up-to-date and accurate incident information with the public. This can be achieved through warnings and alerts, social media and/or traditional media. In IMS, the emergency information officer (EIO) is responsible for public communications and coordinating the communications team.

In larger or more complex incidents, there may be a need to coordinate communication across multiple response organizations. EIOs from the incident response organizations may need to coordinate their messages and/or work together in a joint-emergency information centre (joint-EIC).

It is also important to use plain language and avoid the use of abbreviations. The safety of responders and the general public depends on clear and easy-to-understand communication and messaging.

Internal information

Incident response and communication is a team effort. Sharing accurate and up-to-date incident information is everyone’s responsibility. It is critical that urgent and time-sensitive information is shared as soon as possible with all necessary incident response personnel (e.g. the incident commander, IMS section chiefs, etc.) who require the information to perform their duties. This includes the sharing of information between communities and organizations.

Situation updates should be routinely shared with the section responsible for maintaining situational awareness. This section will maintain and share situational awareness throughout the planning cycle, which includes regularly scheduled meetings as well as a schedule for developing and sharing information products such as situation updates. The section responsible for situational awareness manages information through the four phases of information management. The four phases of information management are to collect, confirm, analyze and share information in a continuous cycle.

The section responsible for situational awareness should share information:

  • with incident responders and leadership
  • with decision-makers such as senior and elected officials
  • between the site(s) and the EOCs
  • between incident response organizations through:
    • liaison officers
    • teleconference calls and meetings which may be pre-planned or as needed
    • situation reports and/or other briefing documents

Note: As incidents become more complex, information must be shared more widely across responders and the organizations they represent.

Plain language

It is important to use plain language and avoid the use of abbreviations. The safety of responders and the general public depends on clear and easy-to-understand communication and messaging.

Information management tools

Common terms

When multiple communities and organizations come together in an incident response, the use of common terms to describe roles, resources and procedures help in effective and efficient communication. This is also known as standardization. The use of common terms also:

  • avoids any confusion and duplication of efforts
  • helps speed up incident response and achieve common objectives

Integrated information management

IMS sets standard procedures to create an environment where responders across communities and organizations share a common understanding of an incident in a timely manner. The incident action plan (IAP) provides all responders with an overview of the objectives, strategies and tactics. IMS forms and other tools to help communities and organizations communicate situational awareness and other incident information.

Effective public information

Effective communication with the public throughout an incident requires common messaging, frequent updates and advance planning. It is recommended to prepare the following ahead of time:

  • an emergency information plan that outlines how the public will be notified
  • pre-scripted messaging and warnings around likely hazards

Telecommunications technology and systems management

Just as information management depends on common terms, it also depends on telecommunications technology and systems that work well together.

Interoperable telecommunications systems

Interoperable telecommunications systems allow for effective and efficient communication between incident responders and the communities and organizations they represent. Where possible, all incident responders involved in an incident should have interoperable telecommunications equipment and systems. These systems may include emergency management software or hardware such as radio equipment.

Communities and organizations should work together ahead of an incident to develop communication methods to ensure effective and efficient communication. This includes:

  • establishing and regularly testing telecommunications technology and systems
  • developing a backup plan in case of telecommunications system disruptions/failures
  • providing training to all necessary personnel for the effective use of telecommunications technologies and systems
  • conducting drills and exercises to practice using the telecommunications technologies and systems with the personnel that would use them in an incident

Telecommunications technology and systems should be:

  • reliable
  • interoperable
  • resilient
  • secure

2.3 Coordination

In order to manage incidents effectively and efficiently, all responders and the communities and organizations they represent work together towards common objectives. This is important as incidents are often not managed alone and require multiple response organizations to work together. IMS can help incident responders coordinate effectively and efficiently through the use of several coordination tools.

Coordination of the incident response effort may take place:

  • within a single organization
  • between a few organizations
  • between many organizations and/or across jurisdictions
  • across the province and/or outside the province

Some incidents are unstable in nature with multiple response organizations facing continuously changing circumstances that can cause an incident to escalate and de-escalate several times. In a system-wide response to incidents of this nature, it is important that response organizations are adaptable in order to achieve common objectives effectively and efficiently.

Coordination tools

Common terms

Common terms help incident responders across different communities and organizations effectively and efficiently coordinate response efforts in a manner understood by all responders (see Section 2.2 – Communication).

Common roles, responsibilities and structures

Common roles, responsibilities and structures allow communities and organizations to work together effectively and efficiently. They also enable requests for personnel and resources from other communities and organizations. As mentioned earlier, this is also known as standardization.

Manageable span of control

“Span of control” is defined as the number of individuals or teams that one individual can manage. The best ratio for span of control at the site is anywhere between three to seven resources reporting to one lead. For safety reasons, it is critical that span of control be maintained. In an EOC or additional incident management location(s), this ratio may be increased to have more people reporting to one lead as long as it does not compromise effective management.


Organizations can only respond if they have the resources to do so. Communities and organizations should train additional responders to provide relief to responders working in prolonged incidents. In cases where communities and organizations are limited in resources, additional capacity can be built by sharing resources through pre-arranged agreements (e.g. mutual aid, mutual assistance agreements etc.) and/or collaborating with partner communities and organizations.

2.4 Collaboration

In order to work together, communities and organizations need to share a common understanding of incident objectives and utilize tools that foster collaboration. Many of the IMS tools already mentioned such as common terms, coordinated information management and common roles, responsibilities and structures can help communities and organizations work together effectively and efficiently.

Effective collaboration is crucial when communities and organizations work together to respond to a large, complex incident. It is important that leadership provides strategic direction that will inform the response activities carried out by incident responders.

It is important to note that some organizations may have regulatory or legislative responsibilities over specific aspects of an incident. For example, fire investigations are the legislative responsibility of the Ontario Office of the Fire Marshal. Effective collaboration ensures that regulatory and legislative responsibilities of response organizations are taken into account when determining incident objectives.

It is important to use IMS to foster collaboration. This includes working together in advance to build trust and understanding between communities and organizations.

Incident responders should understand the importance of working with other communities and organizations through established networks but also through the liaison officer role within the IMS structure (see Section 6.2 – Coordination and command staff (also known as command staff)). It is important to maintain ongoing communication with incident response organizations to ensure actions taken are based on accurate and up-to-date information.

Communities and organizations may need to negotiate an acceptable solution to problems that span across organizational and jurisdictional boundaries. To encourage collaboration and avoid conflict, incident responders and the communities and organizations they represent should:

  • Avoid working independently of one another when developing and sharing information and strategies
  • share situational awareness updates
  • keep all incident responders informed about response activities
  • establish a planning cycle consisting of frequent meetings and through various means of interaction such as teleconference calls

In addition to the above tools, IMS offers other tools to help incident responders collaborate.

Common objectives and plans

The incident commander, unified command or EOC director works with the incident responders to set common objectives for the incident (at the site or in an EOC). This helps incident responders achieve common objectives, also known as unity of effort.

The process of setting common objectives, strategies and tactics includes:

  • developing specific and measurable objectives
  • developing strategies and tactics to meet the objectives
  • measuring objectives, strategies and tactics and making adjustments as needed to effectively manage the next operational period
  • assigning tasks to incident responders
  • developing and distributing plans, procedures and protocols, including the IAP
    • the IAP guides all incident management activities
    • it outlines objectives, strategies, tactics, health and safety requirements and other key incident information to provide a common operating picture of the incident response
    • the delivery of an IAP should be written or verbal

It is important to note that in a complex incident or an incident that involves multiple jurisdictions, a written IAP is necessary to help carry out common objectives and maintain safe operations.

Complex incident objectives and plans

In complex incidents involving multiple response organizations, common objectives will usually be high-level, such as “save lives” or “preserve property.” Each incident response organization will develop specific objectives, strategies and tactics that reflect their organizational responsibilities. For example, in an incident involving emergency evacuations, organizations providing emergency social services may have objectives such as setting up emergency shelters for evacuees.

Training and exercises

It is important for incident responders to have the skills and experience necessary to perform their duties and learn to work with communities and organizations by enrolling in IMS training. Taking part in training and exercises together builds relationships, connections and trust between communities and organizations.

2.5 Flexibility

No two incidents are alike. Flexibility enables communities and organizations to tailor IMS to the size and needs of an incident.

All incidents have common work that must be done such as incident planning. In IMS, common groups of tasks are known as functions. For example, the planning function may be performed by the incident commander or an EOC director in a small-scale incident response. In a complex incident, a full planning section may be stood up to develop multiple IAPs (see Section 3 –  IMS objectives and functions).

IMS allows communities and organizations to use common functions in a scalable and adaptable manner. Incidents may vary in size and require different sections or technical experts. Communities and organizations may use different but interoperable EOC options. While IMS provides flexibility, there are also standardized tools such as common terms, objectives and training. These tools allow response organizations to remain interoperable while meeting the specific needs of an incident.

Flexibility tools


IMS structures for an incident can vary in size. An incident may have an incident commander or an EOC director performing all functions or may have several functional sections and positions stood up and staffed by a large number of incident response personnel.


IMS structures should adapt to the response needs of an incident. For example, a chemical spill may require scientific and technical experts, while a serious motor vehicle accident may not require such experts. IMS enables incident responders to adapt to the needs of an incident and those affected by it.

Responsive to community needs

The goal of an incident response is to manage and lessen the consequences for those affected. To maintain community safety, incident response personnel handling communications should communicate to the public in a clear and easy-to-understand manner and be responsive to the needs of a community.