You can create a new metric while you are viewing a dossier.
Subtract the values of one metric from the values of another metric, such as
Revenue Forecast - Revenue. Calculate a monthly average by defining
Yearly Profit / 12. If a dossier displays sales by dollar amount for a particular region, you can create a derived metric to view the same data in millions, by defining
Dollar Sales / 1,000,000.
Derived metrics are metrics that you can create based on existing objects on the dossier. A derived metric performs a calculation on the fly with the data available on a dossier, without re-executing the dossier against the data source. You can save and display derived metrics on the specific dossier in which they are created. Only objects that currently exist in your dossier are used to create a derived metric. If a derived metric requires data that is not available in the Datasets panel, you must update and resave before the new data appears.
Derived metrics calculate subtotals and dynamic aggregation both for functions that have a default dynamic aggregation (such as sum or minimum) and for functions that do not have a default dynamic aggregation (such as average and count distinct). See the In-memory Analytics Help for more information about dynamic aggregation, as well as a list of the corresponding functions.