Emergency Services/Critical Infrastructure Analysis Methodology

Emergency service providers have well-defined missions that require trained personnel operating specialized tools and equipment that requires the services of critical infrastructure (CI) for execution. However, the relationships within and between these CI sectors are not always well understood. This article proposes a methodology to understand this “interconnectedness” within and between sectors by: (a) bounding the problem; (b) describing the functional interdependencies between CI sectors; and (c) providing a means to evaluate the effects of a disturbance. The insights to be gained from this methodology and analysis may allow decision makers to identify areas for future investigation or investment leading to increased capability and resilience.

Define the Analysis Boundary & Scope

To begin, stakeholders and the boundaries of their problems must be identified. The emergency services CI sector is divided into autonomous organizations with individual missions. In addition to being identified as a “critical infrastructure sector,” these organizations are increasingly interdependent with other CI sectors in order to successfully execute their own missions.

Using the U.S. Department of Homeland Security’s CI definitions, the stakeholders for the emergency services sector are: emergency medical services, fire and rescue, emergency management, and law enforcement. These entities – such as a local police department – have well-defined jurisdictional areas within which they operate on a day-to-day basis. Other sectors have much less well-defined boundaries. For example, the electricity grid and the transportation network extend across jurisdictional boundaries. To conduct the analysis, it is important for stakeholders to agree to a common boundary within which the analysis will occur.

Once the boundary of the analysis is established, the stakeholders must establish the service that is required, from whom it must be obtained, and to whom it must be delivered. Each of the emergency services sector agencies have their own specific mission and objectives, but will rely on common CI sectors – for example, the transportation, energy, water, and communications sectors. For instance, the emergency medical services may be interested in the effects that a loss in communications would have on their ability to deliver service to their jurisdictions (perhaps an entire county).

Finally, it is necessary to depict and quantify the nature of CI inputs to the various emergency services. In other words, the fire service has fire stations wherein apparatus is stationed (nodes) and requires roads (links) necessary to respond to a call for service. With the above information in hand, an analyst may begin to develop a context diagram that shows the entities, the boundaries of the system, and the interactions or interdependencies of that system. Subsequently, the following must be determined: what the analysis questions are; what the desired output of the systems is; and what type of evaluation the stakeholders desire.

Develop the Logical & Functional Model of the Problem

The second step is to identify the types of functions or activities each of the stakeholders must execute, and the interfaces used in support of the emergency services’ mission objectives. In a simplified example, the police department receives a call for service. Responding to this call for service requires that services from the communications, energy, and transportation CI sectors are available. In this example, command and control requires communications services, fuel and electricity are supplied through energy services, and surface roads are available through the transportation sector. Without these CI sectors, law enforcement may not be able to respond to their entire jurisdiction (e.g., due to blocked roads), may have to re-route (causing inefficiency), or use alternate communication means (preventing timely updates to their command and control). Compounding the issue is that the communications and transportation sectors are depending on the availability of the energy sector as well.

The information required to execute the analysis must be obtained from the stakeholders; walking through illustrative scenarios is frequently useful in gathering this type of information. Typically, questions such as those that follow, are used in conjunction with the scenario:

  • Thinking about the scenario, who is affected? What processes, technology, and training areas are associated with the mission?

  • What CI services are needed to perform the operations? Must they be available at 100 percent (e.g., without a specific bridge, response time increases by five minutes)?

  • Can the output and input of the CI services be quantified (e.g., one cell tower that also supports a repeater service’s one-quarter of the county)?

  • What can make the nodes fail? The links (e.g., generators powering the dispatch center have a two-day supply of fuel)? 

With the answers to these types of questions, a preliminary concept of a model emerges, as shown in Figure 1. This is an example of a model that shows the intra- and inter-sector interactions. By engaging with the stakeholders, the layers can be defined and the interdependencies can be analyzed, identifying where current connections exist and opportunities for future connections to be made in order to accomplish missions. Often, discussion by the stakeholders is useful in revealing obvious choke points and resource shortfalls without much rigorous analysis. Ideally, follow-on analysis will surface less obvious connections and potential problem areas.

Develop the Analysis Model of the Problem

Once the data has been obtained and preliminary concepts validated by the stakeholders, the final step is to develop an analysis model of the problem. The model may be developed using several tool types found in the systems engineering or operations research community such as a network diagram, an agent-based model, a systems dynamics model, or a discrete event simulation (see Figure 2).

With the analysis model in hand, stakeholders may begin to insert disturbances and observe the perturbations that ripple through the model. The point of such a simulation is to introduce a disturbance into the system and explore the interdependencies within and between CI sectors. The model concept, as shown in Figure 2, could be used to analyze the interdependencies and understand how the emergency management missions are affected in the event of a disturbance that may initially affect any CI sector or sub-sector. Conducting a workshop, or discussion-based exercise, provides an opportunity to discuss the scenario and analysis (see Figure 3).

Based on the analysis, previously unknown relationships between CI sectors or shared resources may be identified. Other potential insights could include CI sectors that are vulnerable to disturbances, requiring strengthening of selected locations or assets (e.g., specific cellular towers or vulnerable substations that service multiple missions and a majority of the population). Lastly, the analysis may bring insights about other stakeholders, requiring additional cooperation and co-usage of the CI sectors. The insights to be gained are only limited by the imagination of the analyst and stakeholders.


By following a repeatable methodology, the emergency services missions, interactions, and interdependencies can be defined and analyzed in a way that allows decision makers to assess their current state of infrastructure and provide a framework for future relationships and courses of action to produce a more resilient community. This example shows an end-to-end process that bounds the problem, models the mission space, and analyzes the interdependencies and gaps of the existing configuration. Using this type of analysis, decision makers can gain insights into where the critical gaps are within their systems and identify areas for future investment to ensure their missions are satisfied in the wake of a disturbance.

David Flanigan

Dr. David Flanigan supports multiple government sponsors in the early stage systems engineering phases of development, working with government, industry, and academic organizations to plan and execute analytical studies in support of advanced concepts and integrated acquisition strategies. He holds the following degrees: B.S. in Physics from the University of Arizona; M.S. in Information Systems and Technology from the Johns Hopkins University; M.S. in Systems Engineering from the Johns Hopkins University, and a Ph.D. in Systems Engineering and Operations Research from George Mason University.

Steven Taylor

Steven Taylor has experience with state and local government homeland security and emergency management including terrorism prevention and protection. He has Incident Command Systems (ICS) training and operations experience with a focus on all-hazards emergency management mitigation, planning, and preparedness. His interests include dependency and interdependency identification and understanding. He holds the following degrees: B.S. In History and Environmental Biology from Heidelberg University; M.P.A. In Environmental Policy and Natural Resource Management from Indiana University.



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