Cross-project dependency
A cross-project dependency is a link between tasks in two different projects, where work in one project waits on work in another. They are the dependencies most often missed, because each project's plan shows only its own side.
Programs and portfolios are full of them: an app release waits on another team's API, a training rollout waits on the system it trains people for. Each project manager sees their own tasks on time, while the link between them is where the delay is.
Managing them means putting both sides in one view, so a slip in the upstream project shows as a forecast date in the downstream one.
Worked example
| Task | Duration | Depends on | Scheduled | Total float | After the delay |
|---|---|---|---|---|---|
| 1. API: build endpoints | 12 days | None | Days 1 to 12 | 0 days | Days 1 to 17 |
| 2. API: release | Milestone | 1 | Day 13 | 0 days | Day 18 |
| 3. App: build screens | 8 days | None | Days 1 to 8 | 5 days | Unchanged |
| 4. App: integrate API | 4 days | 2, 3 | Days 14 to 17 | 0 days | Days 19 to 22 |
| 5. App: release | Milestone | 4 | Day 18 | 0 days | Day 23 |
The delay: API: build endpoints takes 5 days longer.
The app team finishes its screens on day 8 but cannot integrate until the API is released on day 13. If the API team slips 5 days, the app release moves from day 18 to day 23, although nothing in the app project is late.
Open this example in the free delay simulator to change the durations, the links or the delay and watch the schedule move.