Plan Constants are names (e.g., @BenPct) that you can use in place of numbers (e.g., 0.03) in building your Plan Definition. Plan constants reduce the complexity associated with coding plans that have many tiers of participants. For example, a large public system may have very similar benefits that vary in small ways such as the benefit multiplier, eligibility age, or deferral age. Additionally, plan constants allow key provisions that apply to a particular tier to be coded and viewed in a central location. For example:
Plan Constants can be entered in place of numbers anywhere you see 
:
- Benefit definitions > eligibility conditions and exceptions
- Benefit formula components > constant component type > constant values
- Benefit formula components > accrual definition type > constant and variable accrual rates
- Accrual basis components > constant component type > constant values
- Payment form definitions > commencement age and deferral period
- OPEB plan definitions > full eligibility conditions
Plan Constant values are assigned in your Plan Definition. Within the Plan Constants topic, check Set values for Plan Constants, select the coded field upon which the plan provisions vary, and enter the numeric value for each database code. The numeric values must adhere to the same validation rules that would apply if plan constants were not used (for example, a plan constant referenced as an eligibility age must be between 15 and 99). Usually, this means that Plan Constant values cannot be missing -- with eligibility conditions and exceptions being a special case. You can also create New plan constants or Add/Omit existing Plan Constants. Any Plan Constants already referenced by the Plan Definition will automatically be shown. Click the Ref's button to see where Plan Constants are used within the Plan Definition, or Edit the library entries where Plan Constants are referenced. Click the Transpose button to switch the display from codes by plan constants to plan constants by codes, or vice versa.
The Plan Constants library allows you to define the the variables used as Plan Constants. Give each Plan Constant a Name and optionally enter a Description. The name (limited to 30 characters) may contain letters, digits, and underscores. All names must start with @, if you don't type in the @, ProVal will automatically add it for you. A Plan Constant must be created first before you can reference it (for example, you can't create a new Plan Constant while editing a Benefit Definition).