The Collaboration to Clarify the Costs of Curation (4C) project will help organisations across Europe to more effectively invest in digital curation and preservation. Making an investment inevitably involves a cost and existing research on cost modelling provides the starting point for the 4C work. But the point of an investment is to realise a benefit, so work on cost must also focus on benefit, which must then encompass related concepts such as 'risk', 'value', 'quality' and 'sustainability'. Organisations that understand this will be more able to effectively control and manage their digital assets over time, but they may also be able to create new cost-effective solutions and services for others.Existing research into cost modelling is far from complete and there has been little uptake of the tools and methods that have been developed and very little integration into other digital curation processes. The main objective of the 4C project is, therefore, to ensure that where existing work is relevant, that stakeholders realise and understand how to employ those resources. But the additional aim of the work is to closely examine how they might be made more fit-for-purpose, relevant and useable by a wide range of organisations operating at different scales in both the public and the private sector.These objectives will be achieved by a coordinated programme of outreach and engagement that will identify existing and emerging research and analyse user requirements. This will inform an assessment of where there are gaps in the current provision of tools, frameworks and models. The project will support stakeholders to better understand and articulate their requirements and will clarify some of the complexity of the relationships between cost and other factors. The outputs of this project will include various stakeholder engagement and dissemination events (focus groups, workshops, a conference), a series of reports, the creation of models and specifications, and the establishment of an international Curation Costs Exchange framework. All of this activity will enable the definition of a research and development agenda and a business engagement strategy which will be delivered to the European Commission in the form of a roadmap.The consortium undertaking this project includes organisations with extensive domain expertise and experience with curation cost modelling issues. It includes national libraries and archives, specialist preservation and curation membership organisations, service providers, research departments and SME's. It will be coordinated by a national funding organisation that specialises in supporting the innovative use of ICT methods and technologies.