How to add calculations in SSAS cubes

One of the most useful aspects of a Business Intelligence system is the ability to add calculations to create new measures. This centralises the logic of the calculation into a single place, ensuring consistency and standardisation across the user base.

By way of example, a simple calculation for profit (Income - Expenditure) wouldn't be provided by the source database and historically would be implemented in each and every report. In a data warehouse and/or cube we can create the calculation in a single place for everyone to use.