Defence R&D of critical technologies has played a vital impact on the economy of the developing country. As the development of critical technologies is a major challenge for the developing nation and acquiring through foreign collaboration puts a major impact on the nation's economy and restricts independent exploitation for further R&D. Therefore, Cost estimation becomes vital in the decision-making process in defence research projects and it is critical to have the estimation as accurate as possible. The main objective of this study is to propose a cost estimation model with special emphasis on the cost-risk estimation that complies with the research projects undertaken by DRDO, India. Thus, cost estimation of the critical technology at the early design stage in defence research projects has always been a difficult task as there is little knowledge about the existing resources, development and operational features. For decades researchers have been focusing on developing efficient cost estimation methods. Yet their scarce access to cost information and real- time development scenario becomes a challenge for cost-risk estimation. The methodology was developed after studying the cost estimation methodology of defence research projects of India and other foreign nations. The article intends to provide an efficient manner of cost-risk estimation concerning R&D in India.

Keywords : Cost Estimation, Cost-Risk Estimation, Defence R&D Projects