Global variables enable you to model a 'what if?' analysis on the dashboard. With the calculation engine, it is very easy for the analyst to set up a calculated metric that weighs/changes/forecasts an existing metric.
Creating a global variable
When you create a new global variable, you must write formulas using BIME's calculation engine. If you are unfamiliar with writing formulas in BIME, see Formula writing rules reference.
- In the Query Builder, click the Calculation engine icon ().
- Select the Global variable option.
- Type a name for your global variable.
- Enter maximum, minimum, and default values. For example values see, Types of global variables.
- Click Save when finishedNote: You will not be able to access your global variable until you create a calculation.
- In the Calculation engine menu, select any option.
- Select your global variable from the Select a field drop-down list.
- Enter your formula.
- Click Save to finish your calculated metric or attribute.
- Add your calculated metric or attribute to the frame by clicking the + button. Once you add your global variable to the frame, it will automatically be added to the Filters bar.
Adjusting global variable values
While you cannot edit the minimum or maximum values, you can adjust the default value.
To adjust the default value
- Click on the global variable filter on the Filters bar. The global variable menu will open automatically.
- You can also access the global variable in the Result manipulation menu ().
- Drag the circle across the bar to increase or decrease the default value. You can
also type a new value in the box underneath the bar.
- Click Apply when finished.
Your value is now adjusted.
Types of global variables
Global variables can either be a numeric or percentage multiplier. Both types of multipliers serve different purposes when calculating a 'what if' analysis.
A numeric multiplier models actual changes in a metric. For example, what if the price per gallon goes from $x to $y? Or what if the retail price index drops from $x.xx to $y.yy?
In this case, the default value should be the current result, and the minimum and maximum set to cover both the worst and best case scenarios.
A percentage multiplier is used to model the percentage change of a metric. For example, what if postage costs go up 25%? Or what if your available staff reduces by 10%?
When using a percentage multiplier, the default value should be one, so the initial number is displayed correctly. The minimum and maximum can be whatever is necessary, as long as the values are integers.