# 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.