You may be familiar with the concept of "base lining" in which a project's data is stored so that you can compare what actually happens (also called the "track"), during a project with what you thought would happen when you planned it.

You typically store a "baseline" so that you could later see how the time and monetary budget have shifted from the budgeted to the actual.

Once you have baseline data, one could write simple formulas of calculation on the User sheet.

Now, typically programs like Microsoft Project and WBS (Work breakdown structure) systems store a single baseline, but experience in managing real-world projects has shown that projects don't have one single lifecycle, their plan typically gets redesigned several times along the way, so if you honestly want to track a project and calculate how budgeted vs actual changes over time, then the only real way you can trace and see what's happening in a project is "multiple baselines".

To use the baseline snapshot feature, once you're confident your plan is ready, click the little camera icon and a spreadsheet will be created that stores all the values for that project. This spreadsheet is named "Snapshot_[current date]([snapshot's number])" depending on how many times you click the camera.

In this way you can do useful things such as pressing it once per month to store the "monthly project state". One idea of how to use multiple snapshots would be to use the "Export All" feature it to export all Snapshots to Excel and then use Excel's analysis tools to graphs changes in budget.

Click the film strip icon   and choose Add Snapshot.

To see Snapshot use the tab strip on the bottom to select the particular snapshot you'd like to view or choose View- >Project Views->[Name of Snapshot] or click the film strip icon   and choose it.

To delete a snapshot

Follow the procedure above to view the snapshot sheet you want, then click icon  and choose Delete Snapshot.

{A dialog will ask you if you really want to do this. Click YES and the sheet will be removed. }

Using a similar technique you might instead show the percentage of error... or any other comparison operation you dream up as being of relevance to your project.