> For the complete documentation index, see [llms.txt](https://docs.reorc.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.reorc.com/semantic-modeling/cube/custom-measure/calculating-period-over-period-changes.md).
# Calculating Period-over-Period Changes
### **Use Case**
Calculating period-over-period changes is essential for tracking trends and growth in key business metrics such as clicks, orders, and revenue. This guide explains how to compute period-over-period comparisons, such as week-over-week or month-over-month changes, using Reorc's semantic capabilities.
### Example: Month-over-Month Change Calculation
To calculate a period-over-period metric in Reorc, follow these steps:
**Step 1: Create the Base Measure**
* Add a new measure, `no_of_member`, and define the formula. For example, use `COUNT(DISTINCT member_id)` to count distinct members.
**Step 2: Create the Compared Measure**
* Add another measure, for example, `no_of_member_lm` having the same formula with base measure
* Enable the **Reporting Period** feature and set the time range to **Last Month**.
**Step 3: Calculate the Period-over-Period Change**
* Create a new measure that calculates the change between the current month and the last month.
### **Conclusion**
Reorc's rolling\_window feature allows for flexible and efficient calculation of period-over-period changes. By defining reporting period and calculated measures, users can easily track performance over time and derive meaningful insights from their data.