When I run a Certified Scrum Product Owner class, I talk about the necessity to prioritize the Product Backlog. Mike Cohn found the idea in the work of Karl Wiegers first:
Customers are never thrilled to find out they can’t get all the features they want in release 1.0 of a new software product (at least, not if they want the features to work). However, if the development team cannot deliver every requirement by the scheduled initial delivery date, the project stakeholders must agree on which subset to implement first. Any project with resource limitations has to establish the relative priorities of the requested features, use cases, or functional requirements. Prioritization helps the project manager resolve conflicts, plan for staged deliveries, and make the necessary trade-off decisions. – Karl Wiegers.
Wiegers created a tool: Relative Weighting, that helps Product Owner to prioritize features. The full article of Wiegers you will find here: First Things First: Prioritizing Requirements, Karl E. Wiegers. The excel spreadsheet that helps you to calculate the business value you find also: Excel Tool.