1. A method of reducing risk associated with a task, comprising: obtaining a plurality of tasks required to achieve an overall task; determining risk impact of each task, the risk impact being an impact of each task on the likelihood of failure of the overall task; computing, by a processor, risk of overall task based on risk impacts of the tasks; and utilizing said risk impact of each task to reduce said risk of overall task, including determining a schedule for performing said each task based on said risk impact and determining whether and when to perform the task based on said risk impact, wherein the determining risk impact of each task includes estimating one or more parameter values and upper and lower bounds associated with said each task, constructing probability distribution for said one or more parameter values within its value range, and determining a variance of the probability distribution, and wherein the schedule for performing said each task includes scheduling the tasks in the order of declining variance and dependency of the plurality of tasks, wherein the scheduling includes: beginning with a first list that initially includes tasks that have no predecessors, sorting the tasks in the first list in an order of declining risk impact, creating a second list which is initially empty, and performing following steps until the first list is empty: choosing the task with largest risk impact from the first list; marking the chosen task as considered; removing the chosen task from the first list; appending the chosen task to the second list; if the chosen task is a predecessor to a second task, marking the chosen task as done for purposes of the second task that is a successor to the chosen task; if all predecessors of the second task have been marked as done, adding the second task to the first list, and resorting the first list in the order of declining risk impact, wherein the predecessor to the second task is a task that needs to be performed before the second task can be performed.