---
title: Period vs. previous period block
slug: analytics/docs/j25q-period-vs-previous-period-block
docTags: 
createdAt: 2026-07-20T15:44:27.406Z
---

Use the period vs. previous period block to compare a metric between the current and preceding periods.

Configure the block with the following fields:

- **Measure** – Select the measure for comparison. This can be a dataset property such as a column, a derived column, or a block.
- **Comparison type (using)** – Choose one of the following options:
  - **Absolute change** – Calculate the absolute delta between the current and previous values.
  - **Percent change** – Calculate the change since the previous period, expressed as a percent of the previous value.
  - **Percent of previous value** – Express the current value as a percent of the previous value.
- **Periods ago** – Determine the number of periods in the past to use as a baseline.
- **Filter by** – Utilize the filter by field to filter to a specific set of records before comparing the period and the previous period. Use the following comparison operators (string comparisons are case-insensitive):
  - **is** – Checks if the left side equals the right side.
  - **is not** – Checks if the left side does not equal the right.
  - **contains** – Determines if the left side string contains the right side as a substring.
  - **in** – Verifies if the left side is present within the set of values on the right side.
  - **\<, >, >=, ...** – Applies mathematical operators.
- **For each** – Traverse through the elements in the dataset using this field to choose attributes and make the process more specific.
- **Filter by** – Add additional filters using this section.

## Example

To compare content view time for **Ads Plus** and **Premium** subscribers against their play time from the previous period,

1. Select the **Total Time Viewed(TTV)** metric as the measure.
2. Select Absolute change as the comparison type.
3. Set the baseline period as **1 period**.
4. Select the **Users** dataset in the **for each** field.
5. Add a filter and select **subscription\_tier** as the filtering property and **Ads Plus** and **Premium** as the values.
6. Click **Run**.

![oa-met-ttv.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/5t2OYaCLkXkdhXc2aJwya-20260720-144906.png)

## Output

The output of the period vs. previous period block is a metric that shows the comparison result or difference between the current period and the previous period.