The study shows how to assess the schedule reliability with available reserves of time in noncritical operations. The basis for assessing the reliability is the probability index of plan fulfillment, which is calculated according to known methods based on the beta-distributed random variables. The critical path operations postulate the highest probability of failures. Time reserves in non-critical operations of private flows have a compensating effect on the impact of the failures (delays) occurred on the critical path. The appropriate dependence for accounting time reserves in non-critical operations and calculated values of probability is proposed. In case of necessity of increasing the level of organizational and technical reliability the technique of changing the order of development of particular fronts based on the prediction of possible failures is proposed. The necessary computational techniques are given.