Defining advanced time series variables

Add a financial model stream that does not contains any cost or benefit values by using time series variables. A stream that uses the Variable type represents a random variable that changes over time. You can apply yearly discount rates to time series variables.

3 Populate the stream with data by using the graph paper grid, a spreadsheet, or the calculator. When you refer to independent variables from the Calculator or Project Variables tab, type the independent variable stream name in single quotation marks and specify the time period in square brackets; for example:

Variable	Description
PERIOD	The period that the calculator tape is saved to. This value is displayed on the slider in the calculator.
CURRENTPERIOD	The period that represents the current date
STARTPERIOD	The starting period in the model
DELIVERYPERIOD	The selected delivery period
ENDPERIOD	The last period in the model
PERIODSPERYEAR	The number of periods in each year that are configured for the current project

When you use independent variables, the period might also be the result of an expression. For example, the following expression refers to the number of employees in the previous period:

5 By default, the discounted value from the variable stream for the given period is displayed. To return a value that is not discounted, use the undiscounted keyword:

6 To sum all costs or all benefits for a given period, use the allCosts and allBenefits streams, which are predefined collections.

To	Do this
sum all cost streams for a period	Use the allCosts stream. For example: allCosts[PERIOD] To sum all costs or benefits over a range of time, specify that range.
sum all benefit streams from the delivery period to the end period	Use: allBenefits(DELIVERYPERIOD..ENDPERIOD)
sum all cost and benefit streams	Use the npv function: npv(CURRENTPERIOD..ENDPERIOD)

7 Where expressions are used, you can use and nest conditional expressions. The conditional expression is the same as used in Java and JavaScript:

For example, for a conditional expression that returns 0 before the CURRENTPERIOD otherwise returns 1, use the following format:

You can use conditionals to test boundary conditions and to avoid periods that are out of range, as shown in this nested example:

newCustomers = 'numCustomers'[PERIOD] - (PERIOD-1 >= 0 ? 'numCustomers'[PERIOD-1] : 0)

8 Click Run Simulation. The distribution of all time series variables is sampled and found through Monte Carlo simulation.