# The Set up forecast tab

Use the Set up tab to define the time period for your forecast. If you are generating a multivariate forecast, you'll also use this tab to define the variables for the forecast.

The following options, which are applicable to both univariate and multivariate forecasts, must be set on the Set up tab.

- Forecast period start
- The start of the forecast period. A period is the smallest time interval between neighboring points in the data.

- Forecast period end
- The end of the forecast period. The forecast period end field is populated automatically to reflect the last member on the dimension.

- Save statistical details as comments
- Enable this option if you want to save statistical details as cell comments. For performance reasons, the option to save statistical details as comments is only available if the scope of the forecast is less than 25 time series. For more than 25 time series, the option is disabled.

For a multivariate forecast, you must also specify the forecast variables. You can define one or two variables.

- Click Add variables.
- On the Multivariate forecast page, select the Cube
that contains the variable that you want to use in your forecast.
The list of available cubes is automatically filtered to include only cubes on the same Planning Analytics database that share the same time dimension as the cube for which the forecast is being performed.

- On the Selected members panel, select the members that identify the
variable you want to use in your forecast.
The Selected members panel initially displays the default hierarchy for each dimension. If you want to select a member from a different hierarchy, click on any dimension tile, then click Replace hierarchy.

- Select the Include future values option if you want to include future
values for the specified variable when generating a forecast.
If the historical data include contains less than 64 data points, the future values for variables will not be considered in the forecast.

- If you want to define a second variable, repeat steps 1 through 4.