Mailchimp data in Power My Analytics is reported as lifetime totals, so the List Member Count and List Unsubscribe Count fields show running totals rather than daily activity. This guide shows you how to turn those running totals into a day-over-day view of your audience using a Data Studio time series with a Running Delta calculation, plus a logarithmic Y-axis to keep the chart readable.

Also asked as

• How do I report Mailchimp subscribes and unsubscribes over time?
• How do I show daily list growth from Mailchimp in Data Studio?
• How do I see how many people subscribed or unsubscribed each day in Mailchimp?
• How do I chart new members and unsubscribes per day instead of a running total?
• How do I use Running Delta with List Member Count and List Unsubscribe Count?
• Why does my Mailchimp member-count chart look like a flat line?

Why a Running Delta?

The List Member Count field (shown as Stats Member Count in the Schema Explorer) comes from Mailchimp's List Growth report and reports the total subscribed members on your list. List Unsubscribe Count is its List Growth counterpart and reports the total number of people who have unsubscribed. Because both are running totals, plotting them directly just shows two slowly rising lines.

Data Studio's Running Delta calculation fixes this by charting the difference between each day and the day before. Applied to List Member Count, it shows the net change in your subscribed members each day (sign-ups minus unsubscribes and cleaned contacts). Applied to List Unsubscribe Count, it shows the number of unsubscribes recorded each day.

Prerequisites

• Mailchimp connected as a data source in your hub (see How to Connect to Mailchimp).
• A Data Studio report built on your Mailchimp data source (see the Mailchimp Data Connector User Guide).

Mailchimp data in PMA is lifetime data and cannot be backfilled. Daily collection begins on the day you connect your Mailchimp account, so this chart only goes back to that date.

Part 1: Set up the chart

1. In your Data Studio report, add a Time Series chart using your Mailchimp data source. (A Table chart also works.)
2. Set Date as the dimension.
   
   
   
   
3. In the Setup panel, add List Member Count as a metric.
   
   
   
   
4. Hover over the List Member Count metric and click the pencil/edit icon. Open the Running Calculation drop-down, select Running Delta, and click Apply. Your chart now shows the day-over-day change in member count.
   
   
   
   
5. To track unsubscribes alongside members, add List Unsubscribe Count as a second metric, then apply Running Delta to it the same way (pencil icon > Running Calculation > Running Delta > Apply).
6. Confirm the chart is sorted by Date in ascending order (oldest to newest). Running Delta compares each row to the row before it, so the sort order must be chronological for the numbers to be correct.

The first data point will display a very large number. This is expected: that first day has no previous day to compare against, so Data Studio shows the full list size there. Part 2 fixes how this looks on the chart.

Part 2: Fix the Y-axis scale

Because the first data point shows your full list size, it compresses every other value into what looks like a flat line. A logarithmic Y-axis keeps that first spike from dominating the chart.

1. With the chart selected, switch to the Style tab in the Properties panel.
2. Scroll to the Left Y-axis section.
3. Toggle Log scale on.
   
   
   

The logarithmic scale shrinks the large first-day value so it no longer overwhelms the chart, making the smaller daily changes readable for both series.

How to read your chart

To confirm it worked, you should see two lines plotting daily change: one for List Member Count (net members gained or lost each day) and one for List Unsubscribe Count (unsubscribes recorded each day). Use a date range control or set the report date range to focus on any period you want to review; the running totals for that range add up to the net members added and total unsubscribes for that window.

Things to keep in mind

• Data starts at your connection date. Because Mailchimp data is lifetime and cannot be backfilled, the chart begins on the day you connected Mailchimp to PMA.
• Running Delta is display-only. It is a chart-level calculation and cannot be reused inside other calculated fields.
• Keep the sort ascending. If the chart is sorted newest-to-oldest, the daily changes will be inverted or inaccurate.
• List Member Count is a net figure. Its Running Delta reflects sign-ups minus unsubscribes and cleaned contacts, not gross new sign-ups. For totals scoped to a single list, report on List Member Count per list.

Related articles

• Mailchimp Data Connector User Guide
• Show Sends by Day on a Mailchimp report
• How to Connect to Mailchimp
• Mailchimp schema