Periodic Variables

A periodic variable contain a series of values, each one associated with a date.

Note: Cells with a gray background are locked. Cells with a white background can be edited by clicking inside the cell.

Column	Data
Name	The variable name as it will appear on charts. Names can contain any characters and spaces.
Variable Type	Indicates whether a variable is mapped, global or calculated; see the Variable Type table below.
Data Type	Indicates whether variable values are Double or Integer.
Unit Label	Label for units of measurement.
Default Value (Monthly)	Value that will be applied if no variable is mapped from a data source.
Is Currency?	Indicates whether the variable values are currency amounts.
Aggregate Result	If this box is checked, the group-level value of the calculated variable is the sum of project-level values. This option is available only for calculated variables; for details, see Formula Editor.
Aggregation Method	Method used to calculate totals. The available methods are Sum, Maximum, Minimum, Average, and NonZeroAverage.
Rollup Method	Method used to calculate values for different periodicities; available methods are explained in the Rollup Methods table below.
Is Target?	Indicates whether the variable is a target. For more information, see Targets.
Target Type	Maximum means that the variable value must not exceed the target value. Minimum means the variable value must not be less than the target value. Range allows for both minimum and maximum.
Decimal	Number of decimal places in target values.
Ignore Shift	Indicates whether the variable can be shifted. If this box is checked, variable values will not be shifted when projects are shifted. For example, this is used with prices.
Ignore WI	Indicates whether the variable's working interest can be edited. If this box is checked, changes in working interest will not affect this variable. For example, this is used with prices.
Ignore POS	Indicates whether the variable's probability of success can be edited. If this box is checked, changes in POS will not affect this variable. For example, this is used with prices.

Variable Type

Variable types are described in the table below.

Variable Type	Description
Mapped	Variables of this type are loaded from data sources. When you add a mapped variable, a row is simply added to the table, and you will need to map this variable in a mapping template for your data sources.
Calculated	Variables of this type are calculated in Portfolio. When you add a calculated variable, the Formula Editor will be opened (see Formula Editor).
Global	Variables of this type get their values from the Set Globals tab. They are used to enter 'constants' for modeling (e.g. prices or conversion factors), allowing you to avoid loading repeated data, and keep assumptions separate from the portfolio configuration. For more information, see Global variables.

You can also copy variables by using the Create Copy option in the Add menu (or in the context menu).

If a variable is calculated, its formula will be displayed in the Calculated Variable Expression field when you select this variable in the table.

To delete a variable, select it and click Remove.

Rollup methods

Method	Description
Sum	When converting from smaller periodicities to larger periodicities, values of all periods are summed up; for example, when converting from Monthly to Annually, a year will get the sum of values of all months in that year. When converting from larger periodicities to smaller periodicities, the value is divided between smaller periods; for example, when converting from Annually to Monthly, all months will get an equal share of value assigned to that year.
Sum – Time Weighted	When converting from smaller periodicities to larger periodicities, values of all periods are summed up; for example, when converting from Monthly to Annually, a year will get the sum of values of all months in that year. When converting from larger periodicities to smaller periodicities, the value is divided between smaller periods weighted by the number of days in the period; for example, when converting from Annually to Monthly, each month will get a share of value assigned to that year weighted by the number of days in each month. This method is usually used for production volumes.
Average	When converting from smaller periodicities to larger periodicities, values of all periods are averaged; for example, when converting from Monthly to Annually, a year will get the average of values of all months in that year. When converting from larger periodicities to smaller periodicities, the value is assigned to all periods as it is; for example, when converting from Annually to Monthly, each month will get the same value as that assigned to that year.
Average – Time Weighted	When converting from smaller periodicities to larger periodicities, an average of values of all periods is calculated, weighted by number of days; for example, when converting from Monthly to Annually, a year will get the average of values of all months in that year, weighted by the number of days. When converting from larger periodicities to smaller periodicities, the value is assigned to all periods as it is; for example, when converting from Annually to Monthly, each month will get the same value as that assigned to that year. This method is usually used for production rates such as bbl/d.
Last Period	When converting from smaller periodicities to larger periodicities, the value of the last period is used; for example, when converting from Monthly to Annually, a year will get the value from December of that year. When converting from larger periodicities to smaller periodicities, the value will be assigned to the last period; for example, when converting from Annually to Monthly, December will get the value of that year and all other months will get zeroes. This method is usually used for cumulative values.
First Period	When converting from smaller periodicities to larger periodicities, the value of the first period is used; for example, when converting from Monthly to Annually, a year will get the value from January of that year. When converting from larger periodicities to smaller periodicities, the value will be assigned to the first period; for example, when converting from Annually to Monthly, January will get the value of that year and all other months will get zeroes. This method is usually used for opening balances.
Compounded	Values are compounded using the compounding formula when converting both from smaller periodicities to larger periodicities and from larger periodicities to smaller periodicities. For example, when converting from Monthly to Annually, the following formula will be used (R_y is the annual value and R_m is the monthly value): And when converting from Annually to Monthly, the following formula will be used: This method is usually used for interest rates and inflation.
Equal Allocation Balance	When converting from smaller periodicities to larger periodicities, the value of the last period is used; for example, when converting from Monthly to Annually, a year will get the value from December of that year. When converting from larger periodicities to smaller periodicities, the value is assigned to all periods as it is; for example, when converting from Annually to Monthly, each month will get the same value as that assigned to that year.