The product backlog and the business value of each product backlog item is the responsibility of the product owner. The effort to deliver each item may be estimated in story points, or time. By estimating in story points, the team reduces the dependency of individual developers; this is useful especially for dynamic teams where developers are often assigned to other work after sprint delivery. For instance, if a user story is estimated as a 5 in effort (using Fibonacci sequence), it remains 5 regardless of how many developers are working on it