Scenario Bridges

A scenario bridge explains why two or more scenarios differ. It steps from one scenario’s value to the next through the individual effects that separate them, all within one time period.

What it is

Each scenario in the chart gets its own sum bar, and the steps in between account for the gap. What those steps represent is your choice: the assumptions that differ, the line-items behind them, or the levels of a dimension such as region or product.

A scenario bridge stepping from one scenario's value to another through the effect of each assumption

The staircase shape is what the chart editor calls a waterfall chart. A time bridge uses the same shape to explain a difference between periods rather than between scenarios.

When to use it

You need to explain why the realistic case lands below the plan.
You want to show which assumptions are actually driving a gap, and which are noise.
You want that gap broken down by region or product rather than by assumption.

Use a time bridge instead when the two values you are comparing are two points in time within a single scenario.

Configuration

Create the bridge

Click the Chart button in the upper right corner of a worksheet.
Select Scenario Bridge in the chart selection.
Select the node to visualize.
Select two or more scenarios to compare.
Select how the difference should be broken down: by assumptions, by line-items or by a dimension.
Select the time period to show.

Change it afterwards

Setting	What it does
Node	The node whose data the bridge shows. Change it in the chart editor at any time.
Scenarios	Which scenarios appear. Each one you add gets its own sum bar.
Configure Axes	Puts line-items, dimensions or assumptions on the axis. An assumption bridge starts with Years as the data series and Assumptions on the x-axis. A bridge broken down by a dimension starts with Scenarios as the data series instead.
Orientation	Under Bridge Settings. Draws the bars horizontally or vertically.
Show scenario values	Under Bridge Settings. Draws the start and end scenario as their own sum bars around the effects, and turns on the red and green coloring of the deviations. Switch it off and only the effects in between remain.
Show scenario assumption details	Under Bridge Settings, and only for a bridge that steps by assumption. When a shared scenario is used as an assumption, this breaks it out into its own assumptions instead of showing it as one combined bar.

The Configure Axes dialog for a scenario bridge

Break the difference down by dimension

Instead of assumptions or line-items, the steps can be the levels of a dimension, so the gap is explained by region, product or any other dimension in the model.

A scenario bridge whose steps are dimension levels rather than assumptions

There are two ways in, depending on whether the chart exists yet:

While creating the chart, select the dimension as a delta in the configuration wizard.
On an existing chart, choose the dimension in the axis configuration.

Either way, Enable levels as deltas has to be switched on for the levels to be drawn as steps.

The Enable levels as deltas setting

Show line-item variants

The Assumptions dimension carries two separate levels, and picking the wrong one is the usual reason variants do not appear:

Assumptions - Line Items gives one step per line-item. The variants of a line-item are folded into it.
Assumptions - Line Item Variants gives one step per variant.

So to break the difference down by variant, put Assumptions - Line Item Variants on the axis in Configure Axes.

A step carries both the line-item name and the variant name, as Line-item | Variant, only when that line-item has more than one variant and Group assumption effects is off. Otherwise the step carries the line-item name alone.

Good to know

Every scenario you add is another sum bar. A bridge across four scenarios is four sum bars with effects between each pair, which gets wide quickly. Two or three read best.
Dimension steps need Enable levels as deltas. Without it the levels are drawn as ordinary values rather than as steps, which is the usual reason a dimension bridge looks wrong.
The steps do not have to be effects at all. Put nodes on the axis instead and you get a plain build-up, for example revenue and costs stepping down to gross profit.
A long bridge can be shortened by grouping. Netting an assumption’s removed and added contributions into a single bar often makes the chart readable again. See Grouping Assumption Effects.
Assumptions can explain themselves on hover. Give an assumption a description and switch on the tooltip setting. See Showing assumption descriptions.
A trailing * on an assumption means its effect is inverted. The assumption is active in your start scenario but not in your end scenario, so the bar shows what removing it is worth, which points the opposite way from what you may expect. The chart prints a footnote saying so. These bars appear only while Group assumption effects is off. See Grouping Assumption Effects.

Time Bridges: the same staircase, explaining a difference between periods.
Assumption Effects: how each effect is calculated, and how to show descriptions on hover.
Grouping Assumption Effects: net an assumption’s removed and added contributions into a single bar.
Bridges: both bridge types and the settings they share.