12.7. Scope of Parameters
In this lesson, we'll discuss the scope of default values for parameters in Looker Studio and how to apply them in different levels of hierarchy.
- Understand the hierarchy of parameter default values in Looker Studio.
- Learn how to override parameter default values at different levels: report, page, group, and chart.
- Identify the most appropriate level to use for various scenarios.
Understanding the Hierarchy
There are various levels in the hierarchy where you can apply default values for parameters. These include:
- Default (set during parameter creation)
- Report level
- Page level
- Group level
- Chart level
The lower levels in the hierarchy will override the higher levels.
For example, let's say the default value for the parameter percent_increase is 25. When you refresh the report, you may notice it's already 30, meaning the default value has been overwritten.
Overriding Default Values
At the Report Level
To override the default value at the report level, go to File > Report Settings. When a default data source is set, the parameters within that data source will be listed at the bottom, and you can overwrite their default values.
Example: If the default value of percent_increase is 25, you can change it to 30 at the report level.
At the Page Level
You can also override the default value at the page level. To do this, go to Current Page Settings and update the value. This will change the value for the entire page, but not affect other levels.
Example: You can change the percent_increase value to 20 at the page level, while keeping the report level value at 30.
At the Group Level
When you have grouped elements together (such as a chart and a scorecard), you can override the default value at the group level. This won't affect the page or report level settings.
Example: Change the percent_increase value to 45 at the group level, leaving the page level value at 20 and the report level value at 30.
At the Chart Level
Finally, you can override the default value at the chart level by scrolling down to the data tab and updating the value. This change will only apply to the specific chart and won't affect other levels.
Example: You can set a percent_increase value of 50 for one chart, leaving other levels untouched.
Note: If you hard code the parameter value at the chart level, it won't respond to changes at the page, report, or default level.
Which Level to Use?
It depends on your needs and how you want your Looker Studio report to behave. Generally, the group and chart levels are the most useful, as they allow for more granular control and enable side-by-side comparisons. Using report level settings might be confusing, as changes at the page level can override them.
In some cases, you may need to hard code a parameter on one chart and allow the rest of the charts to respond to user input. This enables users to see how different parameter values compare against each other, providing valuable insights into the data.
Real-life example: You may have a report showing a 40% increase in a KPI on one chart, while the rest of the charts respond to the parameter entered by the user, allowing them to see the impact of a 25% increase against the 40% increase for the whole business.