The scope of this project is to produce an International Standard on Cost Estimating in Project, Programme and Portfolio Management, including the key cost estimating principles, practices, and processes that enable the development reliable cost estimates across the life cycle of projects and programmes. The scope will include guidance on the: • Establishment of a cost estimating framework and governance structure; • Definition of cost estimating principles, concepts, inputs, and required data sources; • Application of cost estimating methods and techniques (e.g., analogous, parametric, bottom - up, and expert judgment); • Development, review, validation, and updating of cost estimates throughout the project and programme life cycle; • Treatment of uncertainty and risk in cost estimates, including sensitivity and risk analysis; • Integration of cost estimating with related project, programme and portfolio management processes, such as scheduling, risk management, earned value management, and budgeting. Use of this International Standard will provide guidance on how to define, structure, and apply cost estimating practices that are consistent, transparent, and comparable across organizations and industries. It is intended to be applicable to any type of organization — public, private, or community — and for any type of project or programme, irrespective of complexity, size, or duration. The Standard will complement information contained in related ISO series of standards. The outputs from the application of this international standards will provide inputs into the application of ISO 21508 Earned Value Management, ISO 21511 Work Breakdown Structures and ISO 21512 Earned Value Implementation Guidance and also ensure consistency in cost estimation as part of integrated project, programme, and portfolio management.