In this paper, ways of improving planning, execution and management of projects using Numerical Design Structure Matrix (NDSM) method are presented to address interdependency of feedback and iteration, which is common in engineering projects management. The NDSM is an alternative approach to traditional project management tools such as Program Evaluation and Review Technique (PERT), Critical Path Method (CPM), and Gantt chart that can only allow the modelling of sequential and parallel processes in projects. As a case study, the model is tested on a set of tasks in a complex petroleum oil field development project, where task sensitivity and information variability attributes are derived. By applying the NDSM method, project duration is optimized and hence total cost of the project is reduced significantly.