Differentiation between threats and risks are crucial part of architecture design. Designing and implementing a solution based on threat patterns instead of analysed risks, may lead to unstable and extreme expensive situations.
What is the difference between threat and risk? Threat is a potential issues in the future what we afraid of. Risk is a threat, which we analysed probability and potential (negative) impact. This means threat is more an emotional thing, a kind of theoretical thing, while risk is more practical.
Risks may be used in the course of design by using the following equation:
Risk value = Probability x Potential Impact
Yes, it is a kind of simplification, while for probability and expected impact is usually handled as a scale of non-numeric values. I mean that probability and potential impact may be referred as low-medium-high scale when you cannot calculate anything.
The table above helps you to identify risk you should care about: they are the Critical Risks as a must. For the selected risks you will plan to actions to avoid them (lowering the probability), or the case they occur to handle and minimise the impact. All these actions will have a cost. The cost should not exceed the estimated probability (as percentage) and the monetised potential impact. That is to say, you have to spend time for investigation to get values and amounts to calculate with. Using this approach you will avoid threat-based overspending.
Jumping from the theory to practice I would refer two of my famous examples: aviation and nuclear plants. Both we know that they are so dangerous; if an accident happen, it will be serious, namely they potential impact is high.
Stop for second! Is it a right statement? Practically NOT! Most of the aviation or nuclear accidents are not known by the vox populi, since they are absolutely not serious. What all we now are the serious ones, which we really afraid of! we found a THREAT but not a RISK! If you check the reports, aviation is the safest transportation service and nuclear plant are the safest plants. The reason is that engineers know that the potential impact is extreme high, therefore the processes of operation are planned to minimise the probability.
Get some facts about the fuels and consequences. A 2000 MW nuclear plant uses about 40 tons nuclear fuel (depending on the technology) in 12-15 months cycles, while a coal-plant with the same power burns 15,000 tons of coal daily! Come on! It means a 12-15 months cycle fuel requirement has 5,500,000 - 7,000,000 tons in case of coal fuel, which is 170,000 times more than nuclear fuel!
The nuclear plant results the 40 tons nuclear waste and the coal-plant deflates 13,750,000 - 17,000,000 tons of CO2. Killing thousands of people and making millions ill every year, causing greenhouse effect and so. You know where is the 40 tons nuclear waste to care, but the millions of tons of CO2 are dissipating in the atmosphere with no chance to make it harmless by our current knowledge.
All the serious nuclear disasters with all of their side effects causes less damage as a single coal plant does.
I do not want to vote on nuclear or coal plant side by this article since the question is much more complex, but I think you understood what I do mean about the difference of THREATS and RISKS!
