Gamasutra - Scrum And Long Term Project Planning For Video Games / quote 3 of 3
Customers control scope through the backlog
One major benefit gained from transitioning from deterministic schedules to iterative planning cycles is that the customers assume more control over the schedule and budget by manipulating the scope. This is done by continually prioritizing the list of features that they want in the game (called the product backlog) based on what value is emerging from the real game. The team delivers these features on a regular basis.If the customer decides that the features built up are sufficient for the money spent or if the fixed delivery date demands, then the team can move over to building the production assets and completing the game. The benefit of this approach is that features of less importance to the game are abandoned before a great deal of effort is spent on them. This is in contrast to having the schedule or budget force the decision to cut key features that might be 90% complete.Schedules often don't predict many of the problems which slow down development and don't prioritize the work based on value. Instead they try to optimize the resources to work in parallel and define when everything will complete at the same time. In reality, these parallel efforts rarely stay in pace with one another and the cross-dependencies can slow the entire effort down. This leads to team death marches and critical features being cut in order to meet a delivery date.