When I’m building a Trends insight in PostHog, I often run into the same problem: one product outcome shows up under multiple event names. Instead of creating an Action (or doing mental math across multiple lines), I now combine those events directly inside the Trends chart and track them as one series.
How I use it in PostHog
- I go to Product analytics → Trends.
- In the series picker (where you normally choose a single event), I select the first event I care about.
- Then I add the other related events into the same series using inline combination.
- PostHog treats those selected events as one line on the chart.
What it actually does (important detail)
This combination is a logical OR. In plain English: if any of the selected events happen, PostHog counts it toward that combined series.
Why this matters in practice
For me, this removes the “naming drift” overhead. I can keep my Trend focused on the outcome I’m measuring, even if the product has multiple valid events that represent the same intent (because different teams shipped different tracking names, or the event schema evolved over time). And I get the result immediately, without creating custom Actions just to make a single chart readable.
If you want the official reference for the feature, it’s documented under Trends as “Combine events inline.”
