In construction investments, the total cost of investment is a quantitative estimate of the probable cost in which it is difficult to minimize the gaps associated with risk factors. The objective of the research is to estimate the gaps associated with risk factors in the total cost to reduce the aforementioned gaps. As results, a complex process was obtained in instrumental matters, from the approach of probabilistic scenarios that entails the need to decide the way in which probabilities are going to be expressed. The conclusions were given from decision-making perspectives of the probabilities of gaps occurring through sensitivity analysis that studies the impact they have on a given dependent variable and the variations that this causes in any of the independent variables that make up the problem studied. The estimation of the size and importance of the magnitude of the risk was also determined, for which the level and degree of sensitivity of the impact of the breaches was set. In this research, the methods of scientific research were used, such as modelling; measurement; and the Monte Carlo Simulator [SMC].