Mapping Variables
Most formulas will contain at least one variable (otherwise, the result will be the same for each row in the structure). These variables need to be mapped to a specific value source, such as an issue field, progress, another column, or even another formula.
As you write your formula, Structure attempts to map your variables to well-known fields. If Structure is unable to map a variable, it will be marked with a red warning icon, and you will need to map the variable manually.
To map a variable – or to edit an existing mapping – click the variable's name in the variable list or in the formula and select the appropriate attribute from the drop-down list.
Until all variables have been successfully mapped, Structure will use "undefined" as the value of unmapped variables when calculating the formula.
Naming Variables
Structure recognizes most standard and custom fields. The trick is to make sure you're entering their names correctly:
For one-word names, enter just the field name: summary or priority
For multiple-word names: remove all non-letters and replace any spaces with underscores: story_points
Variable names are case insensitive, so story_points and Story_Points will both map to the same field.
For a comprehensive list of recognized variable names, see Predefined Variables
Even if Structure successfully maps your variables, it's still a good idea to review them!