Calculated measures are very different than calculated columns. Calculated measures are not static, and operate within the current filter context of a report; therefore, calculated measures are dynamic and ever-changing as the filter context changes. You were introduced to filter context in the previous chapter. The concept of the filter context will be slightly expanded on later in this chapter. Calculated measures are powerful analytical tools, and because of the automatic way that measures work with filter contexts they are surprisingly simple to author.

Before you start learning about creating measures, let's first discuss the difference between implicit and explicit measures.

Implicit aggregations occur automatically on columns with numeric data types. You saw this in the previous chapter when the year column was incorrectly aggregated...