Conclusion

From iteration to iteration and release to release, the project falls into a predictable and comfortable rhythm. Everyone knows what to expect and when to expect it. Stakeholders see progress frequently and substantially. Rather than being shown notebooks full of diagrams and plans, stakeholders are shown working software that they can touch, feel, and provide feedback on.

Developers see a reasonable plan, based on their own estimates and controlled by their own measured velocity. Developers choose the tasks they feel comfortable working on and keep the quality of their workmanship high.

Managers receive data every iteration. They use this data to control and manage the project. They don't have to resort to pressure, threats, or appeals to loyalty to meet an arbitrary and unrealistic date.

If this sounds like blue sky and apple pie, it's not. The stakeholders won't always be happy with the data that the process produces, especially not at first. Using an agile method does not mean that the stakeholders will get what they want. It simply means that they'll be able to control the team to get the most business value for the least cost.