Monte Carlo simulation is a quantitative risk analysis technique in which uncertain inputs in a model are represented by probability distributions instead of one value such as the most likely value. It performs risk analysis by building models of possible results by substituting probability distributions for any factor that has inherent variability. It then calculates multiple results using a different set of random values from the probability distributions.  Using this method to analyse the potential risks that could delay the project schedule provides better information than is typically available from using the critical path method by itself. The benefits of this method include the following:

• The probability distributions within the model can be easily and flexibly used, without the need to approximate them;
• Correlations and other relations and dependencies (such as ”if” statements) can be modelled without difficulty;
• The level of mathematics required is quite basic;
• Computer programs make it easy to run thousands of random samplings quickly; and
• The behaviour of and changes to the model can be investigated with great ease and speed.
   

The advent of spreadsheet applications for personal computers provides an opportunity for users to apply Monte Carlo simulation to everyday analytical work.  Microsoft Excel is the dominant spreadsheet analytical tool with which CT RISK can be helpful for building up the customized framework of the technique for the users.