18. For any risk, a range of possible outcomes is more likely. An output probability distribution gives a complete picture of the possible outcomes and recognises that some of these outcomes are more likely to occur than others. An "expected" outcome is the average of all possible outcomes, taking into account their different probabilities.
19. For example, it is estimated that a particular facility will cost £50m to build. The expected cost associated with construction cost uncertainties could be analysed to give the following events and the likelihood of occurring:
| Possible | Difference from | Estimated | Risk |
| 45 | -5 | 0.1 | -0.5 |
| 50 | 0 | 0.6 | 0 |
| 55 | +5 | 0.1 | +0.5 |
| 60 | +10 | 0.1 | +1.0 |
| 65 | +15 | 0.1 | +1.5 |
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|
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|
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|
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| 1.0 | +2.5 |
20. In the above example, the most likely outcome is that of no extra cost, as this outcome has the highest probability. The expected outcome is the sum of each possible outcome multiplied by its probability, i.e. an extra cost of £2.5m. This would need to be calculated in net present value terms, taking account of the time period over which the risk occurs.
21. The number of likely outcomes may vary for each different risk. In the example above, it was felt that five outcomes could be meaningfully specified, including one for a cost saving in the project. However, introducing extra outcomes need only be done if they add value to the qualification process.