David Allen talks about viewing your work both horizontally and vertically.
The horizontal perspective is the process for actually carrying out your work — the five stages for executing your workflow. The vertical perspective pertains to how you define your work.
Allen uses an aerospace analogy to illustrate the six horizons from which to view our work. He defines them in this way (see Getting Things Done, page 51):
- Runway: Current actions.
- 10,000 feet: Current projects.
- 20,000 feet: Areas of responsibility.
- 30,000 feet: One- to two- year goals.
- 40,000 feet: Three- to five- year vision.
- 50,000 feet: Life (mission/long-term vision/values)
Each horizon “drives” the items at the level beneath. In other words, if you want to know where most of your next actions are coming from, there is probably a project (multi-step outcome) at the level above creating them. Likewise, if you want to know where your projects are coming from, there is probably an area of responsibility or larger goal at the level above creating most of them.
I have some nuances to bring to the exact way we should define these horizons, and a new horizon to introduce (the concept of operations, which fits in one way or another within areas of responsibility), but for now it is simply helpful to observe that we need to think of our work in terms of multiple horizons.
The upshot is this: If you want to get something accomplished, you need to break it down into its next-level components. For example, if you have a goal that you want to accomplish (30,000 foot level), you can’t just write it down somewhere and forget about it. Instead, you need to create a project or two (10,000 foot level) whose accomplishment will bring you closer to reaching your goal.
Likewise, when you have a project to accomplish (10,000 foot level), you need to determine what the next concrete actions are (runway level) that will bring you closer to completing your project.
Breaking things down to the next level beneath is a fundamental principle for getting things done.