Would three extra days move your critical path?
Nine tasks, three streams and a go-live date set by the creative chain. Change one duration by three days and the critical path moves to a completely different team, which is the thing a single run never shows you.
Words on this sheet
- Predecessors: The tasks that have to finish before this one can start. Put their IDs here, separated by commas, and leave it blank when nothing has to come first.
- F statistic: The variation between the groups divided by the variation inside them.
Marketing Starter Critical Path Pro engine
After you install, this is the model to open.
What Sets the Go-Live Date?
- In your spreadsheet, click the Sortia icon in the strip of icons down the right-hand edge. No strip? Click the arrow at the bottom-right to open it. You can also use Extensions, then Sortia, then Open Sortia.
- Click Start from a template and put that name in the search box.
- Pick the card with that name and click Load this template. It arrives on a new tab with real numbers already in it.
This one runs on a Pro engine, and every free install includes five full-quality runs on your own numbers, shared across all five Pro engines rather than five for each. After that, Pro is $199/year.
The answer
- Go live
- Day 30 set by the creative chain
- Critical path
- 6 of 9 tasks: brief, concepts, film, legal, load, launch
- Media buying
- 10 days of slack
- Landing page
- 2 days of float on build and QA; one slip flips the path
Nine tasks and three streams that all have to land before the campaign can go live. Click Run and go-live is day 30, driven by the brief, the concepts, the film, the legal review, the load and the launch. That creative chain is the critical path, media buying carries 10 days of slack and the landing page build carries 2. Everybody in the room now agrees the film is what sets the date, and the status meeting starts chasing the edit.
Here is the run that changes the meeting. Quality assurance on a landing page with tracking, consent and three payment paths almost never comes in at the first estimate, so change the landing page QA duration from 9 days to 12 and run it again. Go-live moves to day 31, one day later, and nobody would notice. But the critical path is now the brief, the landing page build, the QA, the load and the launch.
The film no longer sets the date: it has 1 day of slack and the landing page build has none. A three-day change on a task with two days of float moved the management attention of the whole project from one team to another while barely touching the date. That is why a single deterministic run is a starting point rather than an answer. A critical path is not a property of the project, it is a property of the numbers you typed this morning, and any task whose float is smaller than your estimating error is a critical path waiting to happen.
Two things follow. Read the slack figures and treat anything under about five days as critical, whatever the report calls it. And when you have honest ranges rather than single numbers, add optimistic and pessimistic columns to the same table and switch the tool to Schedule Risk, which runs the plan thousands of times and reports how often each task was on the driving path instead of making you find it by hand.
What this cannot tell you is the effect of two changes at once, which is exactly what that simulation is for. To adapt it, put your own tasks in with their IDs and predecessor IDs, then deliberately push the two tasks with the least slack by three days each and see whether your plan is as fragile as this one.
The model
It arrives on a tab called Template: Campaign Path, carrying these columns:
- ID
- Task
- Predecessors
- Duration (days)
- Owner
Once it is in your sheet
- The model arrives with real numbers in it and runs as it stands, so you can press the button first and understand it second.
- Change the numbers to yours. The sheet marks which cells are inputs and which hold formulas, and most labels carry a note explaining the row.
- Press the run button at the bottom of the panel. It is labeled for the tool you are in, and the result lands on its own tab, with a written reading of it beside the figures.
Never used Google Sheets? Start here goes the whole way, in seven steps, and assumes nothing.
Next question
- How many retainers can you afford to lose?What If Two Clients Leave at Once?
- Which launch day is a coin toss against the rival, and which is worse?What launch date has even odds of beating the competitor?
- Which budget hits the lead target eight months in ten, and what do the extra points cost?What spend gives 80% odds of hitting the lead target?
- How many tickets does the event need before break-even is more than a coin toss?How many tickets to sell for 90% odds of breaking even?
- Which part of the conference actually decides the date?Conference Plan: What Sets the Date?
- Which event risks are worth paying to prevent?Event Risk Register
Every model like this one, and the method behind them: Schedule risk analysis.