Parameters are used in cost estimating relationships or parametric formula in your company to calculate estimates - for both labor hours and costs - which are dependent on other inputs. These inputs are called parameters and can be:

• Fixed or pre-defined parameters as explained here
• Automatically calculated or base parameters
• Escalation factors

Fixed or pre-defined parameters can be set up globally for your entire company such as "Program_Audit_Percent_Of_Labor" or they can be:

• Company-wide meaning that you maintain different parameter values for each company, but shared across proposals and projects
• Proposal or project wide meaning that you maintain the parameter values in your proposal or project header and use it throughout the different estimates in your proposal for project e.g. "Number_of_sites_to_install". On proposal-wide parameter can influence multiple formula-based estimates throughout your project
• Estimate-specific meaning the parameter values can change from one estimate to the next in the same proposal or project, but the parameters are defined for the entire estimate
• WBS or Task-specific meaning that the parameter value only applies to that specific WBS or task the individual labor or material estimates are assigned to, and you can enter a different parameter value on a different task
  • For example when estimating software development based on software lines of code, the ESLOC parameter can be defined at task-level and a separate task created for each software program or module
• Resource specific meaning that the parameter value is entered uniquely for one labor resource group in one estimate
• Risk specific meaning a parameter which defines the cost impact (and therefore risk reserve or weighted risk value)
• Bill of material (BOM) or indentured product structure specific, where a parameter can be defined as a BOM option or feature to configure the bill of material (select components, adjust quantities and define item costs or prices)
  • Item specific parameters are unique for a product, service or item. These parameters are not used in formula currently
• Fiscal or calendar year dependent meaning that the parameter value can change from one fiscal or calendar year to the next
  • Escalation factors as well as rates or other factors are often fiscal or calendar year dependent. You can also make parameters vary by calendar month or fiscal period
• A combination of the above scopes, for example a company-wide parameter with separate values by fiscal year.

To create a parameter, open or create a formula and enter the new parameter details into the table where the formula's parameters are listed. To edit an existing parameter, open or create a formula using this parameter and click on the pencil next to your parameter (highlighted below).

The parameter table above and the details popup below allows you to view or edit the parameter description, type and scope, what type of value it is, as well as the parameter's values, as follows:

1. Enter or edit the description of your parameter, making it short enough to quickly read but long enough to describe your parameter in full and avoid it getting mixed up with any other parameter
   • Keep the description unique and put in your group or department name if this parameter is only for use by your group or department or company
2. The parameter ID is generated automatically however feel free to edit this code or ID to make it shorter or more meaningful. It is the parameter code or ID which appears in the formula expression so pay attention to this field. If you do edit it, only use letters, numbers and underscore, and keep it unique
   • Avoid hyphens, parentheses, dots and other special characters in your parameter ID because formula expressions don't like them
3. It is very important to select the correct type of parameter from the list in this table column. The list is shown in the screen shot below
   • Base parameter for parameters which refer to a set of costs defined by filters
   • Rate or factor for a % of a base
   • Sizing input for a question and answer style parameter where the cost estimator inputs a number
   • Escalation factor
   • A change in cost/hrs per sizing input or logarithmic relationship of cost/hr to a sizing input are used for regression analyis
4. Select what type of value will be assigned to this parameter for example is it a number or a percent, or a cost or an effort, or a quantity with its own unit of measure
   • For parameters which represent an amount, check the currency field, which indicates how the parameter's currency is set, typically for base or automatically calculated parameters. You have the option to set the parameter's amount in the estimate's local currency (the currency of the company or dept. of the top-level WBS in this estimate) or in the project/proposal currency (the currency of the project or proposal leading company or dept.)
   • Always specify or select the unit of measure for parameters which are a quantity
   • If the parameter is a value from list, then maintain the allowed values for your parameter in the list. You can only use text-based parameter values in MVEL formula expressions.
5. Next define the Parameter Scope or on what basis do the parameter's values change. For example, is the parameter is set up once and for all for you organization? In that case,  select "global", else select whether it is company-wide, estimate-specific, resource-specific or task-specific.  You can select more than one parameter scope at the same time. Values will be maintained for the combination of whatever scope(s) you select.
   • If the parameter values vary by year then check this box, for example factors vary by fiscal year. The full list of different vary-by options is listed at the start of this article
6. Optionally enter a full explanation of your parameter in the remarks box. Include information about who is responsible for maintaining this parameter and updating it based on historical performance, or if not a specific person then explain how to update this parameter to keep it accurate

7. In the popup which comes one clicking on the edit pencil below, you can view or enter values for your parameter

• The values will depend on what type of parameter you selected for example, in this case, the parameter type is "Company wide" so separate values must be maintained for each company in your organization
• You do not have to maintain parameter values for rates/factors or sizing inputs as you set up your formula. You will have ample opportunity in your estimate, in either the formula popup or the PARAMETERS tab, to input parameter values in your project.

8. In the example below, parameter type of "task specific" has been selected

• Consequently the values must be maintained for each task in your project estimate
• You can edit the columns manually if the wrong columns appear however in this screen the columns to maintain should automatically adjust based on which parameter scope or varies-by option you selected

9. You can optionally define a default  or set value expression for your parameter, which are fired when the parameter or options and features value input panel is called up

• A default value expression is a formula expression (typically a MVEL expression) which is invoked when the parameter values or bill of material option & features popup is called. Default values are only evaluated if the parameter does not already have a value
• Set value expressions are also formula expressions invoked at the same time, but unlike a default value expression a set expression is always evaluated and will overide any existing parameter value assigned, with the expression result. For this reason parameters will a set value expression cannot typically be edited manually by the user in their estimate.