Tuesday, February 14, 2012

Probability and Impact Matrix

Probability and Impact Matrix is a tool for the project team to aid in prioritizing risks. As you know, there may be several risks in any project. Depending on the size and complexity of the project in hand, the risks may vary somewhere from double digits to triple digits. But, do we have the time and money to look into all these risks, let alone the response action. The answer is NO; we do not have such luxury of time. So, it is necessary to find a way to identify those critical risks which needs the most attention from the project team.

Probability and Impact Matrix uses the combination of probability and impact scores of individual risks and ranks/ prioritizes them for easy handling of the risks. In other words, the probability and impact matrix helps to determine which risks need detailed risk response plans. It is vital to understand the priority for each risk as it allows the project team to appreciate the relative importance of each risk.

For example, a risk with a high probability/ likelihood of occurring and which will have a high impact on the project objectives will likely need a response plan.

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The matrix generally used is a 3x3 matrix (with Low, Medium, High rating for Probability and Impact) or 5x5 matrix (with Very Low, Low, Medium, High and Very High ratings for probability and impact).  A sample Probability-Impact Matrix is given below for your reference.

How to use this matrix? If a particular risk has a moderate probability and the estimated impact of this risk is major, then you look into the respective row and column to identify the risk rating. For a moderate probability and major impact, the risk rating in the above matrix is "Medium". The colors are visual indications of the seriousness of the risks.

We will use this matrix in the risk assessment process to determine the risk rating for each risk.