Guide 175 · Conversions · GA4 + Tag Manager
Create a key event from an existing event in GA4: the Create event step, then the star
Some actions have no event of their own. A download of one annual report is a file_download among hundreds, so the key event needs a new event built from it, with a condition on the file name. This guide creates annual_report_download from file_download, marks it, and works out what the count means when the new event only exists from today.
After the steps, the annual_report_download key event appears under the Key events tab in Admin, and the standard reports show it within a day. The worked example below gives the count and the rate to expect.
Download the reference: the annual_report_download key-event reference (JSON) (724 bytes, MD5 ff48db2774f83ee826b8e78d156afca6). It holds the event name, the counting method, the worked-example figures recomputed for this guide, and the checkpoints that prove the key event is recording. The figures in the file are the same figures shown on this page.
What you need
- Marketer access or above at property level. Creating a new event and marking it at the same time needs the Marketer role.
- The source event already collecting, with the parameter the condition needs. Here that is file_download with the file_name parameter.
- The exact file name to match, copied from the link, not typed from memory. In this guide it is annual-report.pdf.
The trace
- Open Admin, then Data display, then Events, then Create event. The create form builds a new event from events the property already collects. It does not send anything new from the site; it relabels what already arrives.
- Name the new event annual_report_download. Event names are lowercase with underscores. The name must be different from the source event, or the new event and the old one become the same row.
- Add the condition: file_name equals annual-report.pdf. The condition reads the file_download event and keeps only the hits where the file_name parameter equals the annual report. Every other download keeps flowing to file_download and never reaches the new event.
- Save the event, then mark it as a key event. The create form offers the marking at creation time. Tick it, so the new event is a key event from its first day. If the marking is missed, the star in the Events table adds it afterwards.
- Check the new event in DebugView. Open Admin, then Data display, then DebugView, and download the report. The annual_report_download event should appear with the file_name parameter. If only file_download appears, the condition did not match, and the file name in the condition is the first thing to compare.
- Wait for standard reports, and read the count from the creation date. Allow up to 24 hours before the new key event shows in standard reports. In the worked example the first week shows 37 key events from 2,100 sessions, which is a session key event rate of 37 / 2,100 = 1.76%. Downloads before creation are not counted, because the event did not exist then.
Dead ends
DEAD END — A CONDITION ON A PARAMETER THAT NEVER ARRIVES. If the file_name parameter is missing from the file_download hit, the condition never matches and the new event stays at zero. Confirm the parameter in DebugView before building the event.
DEAD END — MARKING THE SOURCE EVENT INSTEAD OF THE NEW ONE. Marking file_download makes every download a key event, including the staff handbook and the price list. The new event exists precisely so that only the annual report counts.
DEAD END — EXPECTING THE NEW EVENT TO COUNT OLD DOWNLOADS. A created event starts from its creation date. The 210 downloads of the annual report last month stay inside file_download history, and the new event starts at zero.
End state
The annual_report_download event is a key event from its creation date, counting only downloads of annual-report.pdf. The first week shows 37 key events from 2,100 sessions.
| Figure | Value |
|---|---|
| Sessions in the first week | 2,100 |
| file_download events in the week | 486 |
| annual_report_download key events | 37 |
| Share of downloads that were the annual report | 7.61% |
| Session key event rate | 1.76% |
The share is 37 / 486 = 7.61% and the session rate is 37 / 2,100 = 1.76%, both recomputed in Python 3 and rounded to two places. The figures are a worked example, not a real property.
Sources
- Analytics Help — About key events — marking an event as a key event, the 30-event limit for a standard property, and 50 for Analytics 360
- Analytics Help — Conversions vs. key events in Google Analytics — what a key event is, the event to key event to conversion flow, and where Google Ads conversions appear
Checked 11 November 2026. The click path above is the one in Google's help pages, read 11 November 2026. Creating an event from an existing event with a parameter condition, marking it at creation, and the forward-only counting are as Google documents them. No step in this guide was run inside a live Analytics property, because Admin needs a Google sign-in and this site does not sign in as anyone. The figures on this page are a worked example recomputed in Python 3 with decimal arithmetic, not numbers from a real property. Google moves menu items without warning; if a path on this page no longer matches, the linked help page is the current map.