The risk matrix allows for risk classification. This tool captures the most pertinent information about identified risks and classifies them according to probability of occurrence and level of impact on the project. A project risk is an event that, if it were to occur, would have an effect on at least one restriction impacting timeline, cost or scope objectives. There are known risks – those which have been identified and for which it is possible to plan actions to reduce their impact. But there are also unknown risks – those which cannot be managed proactively.