Business data across your forecasts
Each forecast has its own copy of your business data
There's no single, central record of your business data that every forecast reads from. Your baseline forecast holds one copy. Every forecast scenario you create by duplicating a forecast starts as a copy of that forecast’s business data, taken at the point you duplicated it. A duplicate copies from the forecast you duplicate, which isn’t necessarily your baseline. The first time you open a forecast, sherloc tells you the same thing: “Your core data is stored separately. Anything you change, overwrite or delete applies only inside this forecast scenario.”
From then on, each copy stands on its own. That's what lets you try out a "what if" in a scenario (add a role, change a number) without touching your baseline or any other scenario.
What that means when you make a change
Because each forecast holds its own copy, a change you make in one (your baseline, or any scenario) only applies there. If you want the same change reflected in another forecast, you make it there too.
This keeps every forecast dependable on its own terms: nothing changes underneath a scenario you've already built, just because something moved elsewhere.
Two kinds of change
Business data can change in two ways, and it's worth knowing which one you're doing.
Correcting something already there
You're fixing or replacing an entry that already exists, such as a salary figure that was entered wrongly.
Adding something new
You're bringing in detail that wasn't captured before, such as splitting one bulk entry for "10 developers" into 10 named people, each with their own detail.
Worked example
Round numbers, to show both kinds of change.
Correcting something: on the Staff tab of one forecast, a salary was entered as £40,000 when it should be £45,000. You correct the salary cell there. The other forecast, which started from the same data, still shows £40,000. You'd correct it there too, if you want the two to match.
Adding something new: you onboarded quickly with a single row for "10 developers." Later, in one forecast scenario, you remove that row and add a line for each of 10 named people, each with their own salary. That scenario now holds more detail than your baseline. Your baseline still has the original bulk entry, until you make the same change there.
Neither of these is a mistake to undo. It's just worth knowing that a correction or an addition applies to the forecast you made it in, not to every forecast at once.