Reference lines are a useful feature which can be used to compare, refer to, or measure against the data values displayed in a graph. Reference lines are often used to show whether data has met a certain target. For example, they are often used to see which product category has exceeded the target sale of x.
When working with a fixed target sale, click on the analytics tab and then reference line and set this to your target value by selecting 'custom value' and adding your target value.
![](https://www.thedataschool.co.uk/content/images/2022/10/image-388.png)
However, if you want to adjust the target value and show a reference line according to each selected target value, a parameter is needed.
![](https://www.thedataschool.co.uk/content/images/2022/10/image-390.png)
Click create new parameter in the reference line tab. Now you can set your parameter by a list, range or all your values.
![](https://www.thedataschool.co.uk/content/images/2022/10/image-391.png)
Now you should be able to change the reference line according to the parameter you have set.