Planning a cutover
A broker-dealer is moving its email to a compliant productivity platform with archiving that meets SEC and FINRA recordkeeping rules. The tasks, their durations in working days and what each depends on are:
| Task | Days | Can start after |
|---|---|---|
| A. Freeze changes to the old system | 1 | – |
| B. Export mailboxes | 4 | A |
| C. Configure retention and archiving policies | 3 | A |
| D. Compliance validates the archive | 2 | C |
| E. Migrate mailboxes | 3 | B and D |
| F. Train users | 2 | A |
| G. Cut over and start support | 1 | E and F |
- What is the shortest time to finish everything, and which tasks are on the critical path?
- Which tasks have slack, and how much?
- The export team says B might take 6 days instead of 4. What happens to the end date?
Hint
Work out the earliest finish of each task, counting from day 0. A task can start only when everything it depends on has finished.
Worked solution
Earliest finishes: A by day 1. B by 1 + 4 = 5. C by 1 + 3 = 4. D by 4 + 2 = 6. E starts when both B (day 5) and D (day 6) are done, so at day 6, and finishes at 9. F by 1 + 2 = 3. G starts at day 9 and finishes at day 10.
- The shortest time is 10 working days. The critical path is A, C, D, E, G (1 + 3 + 2 + 3 + 1 = 10). The path through B is 1 + 4 + 3 + 1 = 9 days.
- B has 1 day of slack (it finishes at 5, but E cannot start until 6). F has 6 days of slack (it finishes at 3, and G starts at 9).
- If B takes 6 days it finishes at day 7, later than D. E then starts at 7 and finishes at 10, and G finishes at day 11: one day late. B used its 1 day of slack and the second day moves the end date.
The useful observation for the client: the compliance validation (D) is on the critical path, so getting the compliance team’s time booked early matters more than speeding up training.