Comparison to a different period which relates to the current period—for example, comparison with the last month
Comparison to the same period with a year offset—for example, this month last year
Both forms of this calculation are conceptually the same—it is only the offset that is applied in the calculation that is different. Consider the situation of determining a value for the last month. Here, we perform a base calculation with a monthly offset from the current date. For the last year value, we perform the same base calculation with a 12-month offset. Of course, the 12-month offset can be simplified as one year, but the calculation is the same.
Furthermore, by considering a base calculation in the context of a current date, the logic of prior period calculations can be applied to any...