The Bald Tire Scenario

As you proceed through each of the steps within the scenario below, ask yourself how much risk is associated with what’s being described.

Picture in your mind a bald car tire. Imagine that it’s so bald you can hardly tell that it ever had tread. How much risk is there?

Next, imagine that the bald tire is tied to a rope hanging from a tree branch. How much risk is there?

Next, imagine that the rope is frayed about halfway through, just below where it’s tied to the tree branch. How much risk is there?

Finally, imagine that the tire swing is suspended over an 80-foot cliff with sharp rocks below. How much risk is there?

Now, identify the following components within the scenario. What were the:

  • Threats
  • Vulnerabilities
  • Risks

Scenario Analysis

Most people believe that the risk is ‘High’ at the last stage of the Bald Tire scenario. The answer, however, is that there is very little probability of significant loss given the scenario exactly as described. Who cares if an empty, old bald tire falls to the rocks below?

Was my question about the amount of risk unfair? Perhaps, and I’ve heard the protests before, “But what if someone climbs on the swing?” and, “The tire’s purpose is to be swung on, so of course we assumed that somebody would eventually climb on it!” Both are reasonable arguments. My point is that it’s easy to make assumptions in risk analysis. In fact, some assumptions are unavoidable because it’s impossible to know every conceivable factor within a risk scenario. However, assumptions about key aspects of the risk environment can seriously weaken the overall analysis.

The second point I’d like to make is that, from any group that goes through the Bald Tire scenario, I’ll typically get several different descriptions of what constitutes the threat, vulnerability, and risk within the scenario. I’ve heard the frayed rope described as threat, vulnerability, and risk. I’ve also heard the cliff and rocks described as threat, vulnerability, and risk. The simple fact is that we, as a profession, have not adopted standard definitions for our terms. In informal discussions amongst ourselves, this may not always be a significant problem, as we typically understand what is meant by the context of the conversation. Consider, however, that physicists don’t confuse terms like mass, weight, and velocity, and financial professionals don’t confuse debit and credit even in informal discussions because to do so significantly increases the opportunity for confusion and misunderstanding. This is important to keep in mind when we’re trying to communicate to those outside our profession particularly to sharp executives who are very familiar with the fundamental concepts of risk where misuse of terms and concepts can damage our credibility as professionals and reduce the effectiveness of our message.

A third point is that you can’t have significant risk without the potential for significant loss. In other words, it doesn’t matter how exposed to harm an asset is, if the asset ain’t worth much, the risk ain’t high. This is because risk always includes a value component. If it didn’t, betting a million dollars would be equivalent to betting one dollar.

A final point is that there’s a tendency to equate vulnerability with risk. We see a frayed rope (or a server that isn’t properly configured) and automatically conclude that the risk is high. Is there a correlation between vulnerability and risk? Yes. Is the correlation linear? No, because vulnerability is only one component of risk. Threat event frequency and loss magnitude also are key parts of the risk equation.

So, what are the asset, threat, vulnerability, and risk components within the Bald Tire scenario? The definitions and rationale are described more specifically further on, but, simply stated:

  • The asset is the bald tire
  • The threat is the earth and the force of gravity that it applies to the tire and rope
  • The potential vulnerability is the frayed rope (disregarding the potential for a rotten tree branch, etc.)

What about risk? Which part of the scenario represents risk? Well, the fact is, there isn’t a single component within the scenario that we can point to and say, “Here is the risk.” Risk is not a thing. We can’t see it, touch it, or measure it directly. Similar to speed, which is derived from distance divided by time, risk is a derived value. It’s derived from the combination of threat event frequency, vulnerability, and asset value and liability characteristics.

Having made an issue of terminology, the following paragraphs introduce and briefly discuss some basic definitions.


A reasonable definition for Threat is anything (e.g., object, substance, human, etc.) that is capable of acting against an asset in a manner that can result in harm. A tornado is a threat, as is a flood, as is a hacker. The key consideration is that threats apply the force (water, wind, exploit code, etc.) against an asset that can cause a loss event to occur.


You may have wondered why “potential” is emphasized when I identified the frayed rope as a potential vulnerability. The reason it’s only a potential vulnerability is that we first have to ask the question, “Vulnerable to what?” If our frayed rope still had a tensile strength of 2000 pounds per square inch, its vulnerability to the weight of a tire would, for all practical purposes, be virtually zero. If our scenario had included a squirrel gnawing on the frayed rope, then he also would be considered a threat, and the rope’s hardness would determine its vulnerability to that threat. A steel cable (even a frayed one) would not be particularly vulnerable to our furry friend. The point is that vulnerability is always dependent upon the type and level of force being applied.


In the context of information risk, we can define Asset as any data, device, or other component of the environment that supports information-related activities, which can be illicitly accessed, used, disclosed, altered, destroyed, and/or stolen, resulting in loss. The question is often asked whether corporate reputation is an asset. Clearly, reputation is an important asset to an organization, yet it doesn’t qualify as an information asset given our definition. Yes, reputation can be damaged, but that is a downstream outcome of an event rather than the primary asset within an event. For example, reputation damage can result from public disclosure of sensitive customer information, but the primary asset in such an event is the customer information.


The following definition applies regardless of whether you’re talking about investment risk, market risk, credit risk, information risk, or any of the other commonly referenced risk domains:

Risk: The probable frequency and probable magnitude of future loss

In other words “how frequently something bad is likely to happen, and how much loss is likely to result.” As stated above, these probabilities are derived from the combination of threat, vulnerability, and asset characteristics.

Other Factors

So, where do the cliff and rocks fit into the risk equation? They aren’t threat agents because they don’t precipitate an event and, clearly, they aren’t vulnerabilities that allow an event to occur. Consequently, these components can be considered secondary loss factors because their existence contributes to the magnitude of loss from an event. A real world example would be the fines and sanctions levied by regulatory agencies following an information security event. The regulations and regulators aren’t the agents that commit a breach, so they aren’t threats in the context of the event. They also aren’t a technological, procedural, or other weakness that allowed the breach to occur. Nonetheless, they play a role in how much loss occurs and therefore must be included in our risk analysis. (Note, however, that there are scenarios in which regulators can be classified as threat agents, i.e., when they perform an audit.)

next: The Bald Tire Metaphor

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