# Data Effects Display in Bridge
URL: https://docs.valsight.ai/data-effects-display-in-bridge/
Description: Split the model's own contribution to a time bridge out per node, or group several nodes into one named block.
If you look at a bridge that analyzes differences from one year to the other, you will see the base values for both years and a number of smaller steps that lead from one base to the other. These differences come from two different sources:

* Differences in the model ("Data effects"): "Base data - YoY 2020 → 2021"
* Differences in the simulation ("Simulation effects"): "Base assumptions", "Individual assumptions", ...

Differences in the model are, in most cases, circumstances that you cannot influence (like fixed costs); by default, they are displayed in one large block. If you want to split them up per node or group them together, you can mark the respective nodes in the model and activate the setting in the chart.

## Goal

Break the model's own contribution to a time bridge out of its single block, either into one effect per node or into named groups of nodes such as a combined "price effect".

## Prerequisites

* A [time bridge](/time-bridges/) on your worksheet. Choose one scenario and two years, quarters or months, then select **Bridge between periods (e.g. YoY)**.
* Edit rights on the model the nodes live in, since part of the setup happens in the model editor.

![The bridge between periods option when creating the chart](./images/5147689010.png)![The resulting time bridge with one block for data effects](./images/5094212319.png)

## Steps

### Show data effects per node

1. Open the model the node lives in.
2. Select the node and switch on **Show data effect in bridges**.

   ![The Show data effect in bridges setting on a node](./images/5094212411.png)
3. Go back to the workspace, select your bridge, and set **Data effects** in **Bridge Settings** to **Detailed**.

   ![The Data effects setting in the bridge settings of the chart editor](./images/5148344359.png)![The bridge with one effect per node, each labeled (model)](./images/5094212491.png)

The bridge now shows a separate effect per node, each carrying the node's name with **(model)** appended.

### Group several nodes into one effect

1. In the model editor, fill in the **Group Key** field on each node you want combined. Nodes sharing a group key become one block in the bridge, which is how you build something like a single "price effect" out of several nodes.
2. Set **Data effects** in **Bridge Settings** to **Grouped**.

   ![The bridge with data effects combined into named groups](./images/5094212462.png)

The group key is also the name shown in the chart, so it doubles as the label.

## Verify

Your bridge's data effects are no longer a single block:

* With **Detailed**, one step per marked node, each labeled with the node name and **(model)**.
* With **Grouped**, one step per group key, labeled with that key.

If the block is still whole, check that **Show data effect in bridges** is switched on for the nodes and that **Data effects** is not still on **Total**, which is its default.

## Related

* [Time Bridges](/time-bridges/): creating the bridge in the first place, and how the effects are calculated.
* [Assumption Effects](/assumption-effects/): how the simulation side of a bridge is derived.
* [Grouping Assumption Effects](/grouping-assumption-effects-in-bridges/): the equivalent grouping for assumption effects.