---
title: "Connecting variables in Simulation Models"
slug: "connecting-variables-in-simulation-models"
updated: 2022-06-28T18:32:30Z
published: 2022-06-28T18:32:31Z
canonical: "userguide.dataclassroom.com/connecting-variables-in-simulation-models"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://userguide.dataclassroom.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Connecting variables in Simulation Models

When you have a Simulation model with at least 2 variables, you can define **relationships** between them using the Connections grid.

Variables on the left-hand side of the grid "affect" variables on the top of the grid, if the connection between them has been set to **Active.**

In the example below, the **Light** has been made to affect **Height**. This could be an experiment to see how lighting ("bright" or "dark" environments) affect the height achieved by plants.

![](https://cdn.document360.io/62f8f41e-e041-42c4-b9bc-8ae1eb45d064/Images/Documentation/image-1656094622657.png)

Clicking on the connection point allows you to **define how the variables are connected**, or to activate or de-activate the connection.

There are four possible connection types, which are explained in the articles below:

[Categorical affects Numeric](/v1/docs/categorical-affects-numeric)

[Categorical affects Categorical](/v1/docs/categorical-affects-categorical)

[Numeric affects Numeric](/v1/docs/numeric-affects-numeric)

[Numeric affects Categorical](/v1/docs/numeric-affects-categorical)

### Correlation vs causation

As there is no mathematical difference in the model whether a relationship modelled might in the real world be causative or a correlation, you do not need to specify this in defining the model.

This is in itself an insight into why it can be very difficult to determine cause and effect by experimental studies.

### Hiding variables from the connection grid

To de-clutter the grid, you can click **Hide** by the variable name, if that variable is not going to be needed in that context.