Which stream will move the delivery date?
Three streams run in parallel after kickoff and one of them decides the date. The second is one day behind it, which makes the usual advice to protect the critical path wrong here in a way a bar chart will not show 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.
Work Starter Critical Path Pro engine
After you install, this is the model to open.
When Does This Engagement Actually Finish?
- 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
- Delivery day
- 39 working days, driven by the data path
- Interviews
- 1 day of slack: two days of slip and they set the date
- Materials
- 15 days of slack: a fortnight free
- Critical tasks
- 7 of 9 kickoff, data, model, workshop, report
Nine tasks on one client engagement, in working days. Three things start once kickoff is done: the data stream, the interview stream and the working session materials. Click Run and the engagement finishes on day 39, driven by kickoff, the client data extract, the cleaning, the model build, the workshop, the draft and the final issue. So far this is the answer everybody expects.
Read the slack column and it changes the plan. The working session materials carry 15 days of slack, so they can slip a fortnight without costing you anything. The interview stream carries 1 day. One. That is the finding this template exists to show, and it is invisible on a bar chart. The data path is the critical path, but the interviews are one day behind it, which means the standard advice to protect the critical path and let the rest look after itself is exactly wrong here.
Any interview that slips by two days makes the interview stream the critical path instead, and the date moves even though the data arrived on time. A path with one day of float is not a spare path, it is a second critical path with a rounding error. The right move on a plan shaped like this is to manage both streams and to spend nothing at all on the materials.
Two things about the table are deliberate and worth copying. The interview task is 22 days because that is elapsed time and not effort: eleven interviews at two days of diary lag each is what booking senior people actually looks like, and saying so in the plan is half the value of writing one. And the data extract is owned by the client, because the single longest lever on most engagement dates is somebody who does not work for you.
There is one thing this tool cannot do that people expect it to. Critical Path reads finish-to-start dependencies only and has no lag field, so a wait between two tasks has to be its own row with its own duration. Second run: change the interview duration from 22 to 20 and rerun. The finish stays at 39 and the interview slack goes to 3, which is what two days of tighter diary management buys, and it buys it as breathing room rather than as an earlier date.
To adapt it, keep the ID and Predecessors columns as they are and put your own tasks under them, use elapsed working days rather than effort, and name the client in the Owner column wherever they really own the task.
The model
It arrives on a tab called Template: Engagement Plan, 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 hours will this scope actually take?What Should This Engagement Cost to Deliver?
- What if the partner with the fee book leaves?What Does Losing One Person Cost?
- A consulting engagement risk register ranking five risks by exposure and by mitigation value, since the two rankings are not the same list. Free template.What Could Go Wrong on This Engagement?
- Is your busiest person really the problem?Is Anyone Booked on Two Clients at Once?
- What does one conflict of interest cost you?Who Works on Which Client?
- Which client is quietly about to leave?Which Engagements Renew?
Every model like this one, and the method behind them: Schedule risk analysis.