Unless we know what capabilities we need at the end of the project, and know those somewhere near the beginning of the project, have a Plan to produce those capabilities at the needed time for an anticipated budget, we're going to be disappointed in the result.
Identifying the needed capabilities is the first and most important practice for the success of any project. To achieve the project's objectives or a particular end state, we need to define these capabilities through Measures of Effectiveness. We can do this through scenarios from the customer's point of view. The effectiveness measures describe how well the results from the project enable a business process or fulfill a strategic mission of the business - in this case enforcing the will of the emperor. These measures must be in units meaningful to the decision makers. In the case Darth Vadar.
When we let those needed capabilities emerge we have likely disconnected the products of the project from the mission or vision of the business. Requirements can emerge to fulfill the capabilities. But the capabilities need to be steady and focused on mission outcome, otherwise we are just on a spend plan. We'll have no way to know what done looks like until the money runs out.
Here's an example of an increasing maturity of the capabilities for a health insurance provider network ERP system.
This approach is not usually found in traditional or agile projects. These approaches start with requirements, stories, features - all related to the technical aspects of the project. A Master Plan is developed that shows the needed capabilities (above), the order of delivery of these capabilities, and the dependencies between these capabilities.
The increasing maturity of the project's outcomes is then stated in this map. Technical requirements implement the capabilities, so they need a plan - schedule actually - as well. Small incremental capability delivery is the best approach. This is obvious and the basis of agile, but not always planned that way.
This plan contains all the steps (delivered capabilities) needed to increase the maturity of the of the project from the start. This does not mean we know how these capabilities are going to be delivered, but it does show what DONE looks like at the end of the project. In this example Phase 1 - Go Live.
This approach does not define any specific development process - agile or traditional. It is the basis of success for any development process.
Capabilities Are the Vehicle For Delivering Value
The Capabilities and their Measures of Effective need to remain stable over the life of the project. Without this reached DONE with any sense of budget and schedule will not only be difficult, you will be rubber banding the baseline used to measure your performance. You'll have turn a project into an operational activity. Projects have defined outcomes, defined periods of performance and associated budget. Operations can be fixed budget, open ended periods of performance, and emerging outcomes. But reaching a defined description of DONE becomes much more difficult.