What are conversions/key events?

Setting up conversions is the most typical use case for GA4, and any other analytics tool. Before looking at the details, it’s worth remembering that this is usually NOT so you can track how many conversions you’re getting. After all, if your conversions are purchases or lead forms, you can usually get that from your backend already, and that data has the benefit of being 100% complete and accurate. Rather, it’s to find out where your conversions are coming from, meaning to break down your conversion data by some of the other dimensions available in GA4. We’ll go over many of these in the rest of the sequence and then highlight a typical analysis workflow, but for now it’s good to keep in mind that setting up conversions is only the start of it.

Google’s name for these (“key events”) is fairly new, they used to be called “conversions” but those now refer specifically to events that you use to evaluate and optimize your ad campaigns. We’ll use “key events” from now on because even though it sounds more awkward, it actually describes what’s happening a bit better.

How do I set up key events?

This is the really simple part because “key events” really means “those events that I’m already tracking that I’ve identified as being particularly important to my organisation”. So the first and biggest step is to actually set up event tracking for those events using whatever method you’re using to set up GA4 tracking. Then, in the admin section click Data Display > Events and mark some events as key events. That’s it!

What should my key events be?

This is the more interesting question as we generally find people don’t include enough events to track their micro-conversions. Generally, you’d want to first track your most important events. For online purchases or donations it would be when someone pays (and GA4 automatically marks “purchase” as a key event). If the conversion happens offline, you may want to track that and make that a key event but if that’s too hard, track the website user action that’s closest to the offline conversion. Usually it would be someone filling out a lead form, booking an appointment etc.
Finally to track micro-conversions, consider the other ways the user can engage with your website. If some of these are more valuable (eg. downloading a PDF sales brochure), these could also be key events.

What are the other GA4 key event metrics?

• The key events metric just counts how many occurred. If a user completed multiple key events (even duplicate ones), they will be included in the count.
• The user key event rate counts what percentage of users completed a key event. Because it’s user-based, duplicate key events from the same user are not counted.
• The session key event rate counts what percentage of sessions completed a key event. Because it’s session-based, duplicate key events from the same session are not counted (but if a user completed the same key event in multiple sessions, they would be).
• The above metrics also exist for specific events. For example if you marked add_to_cart as a key event, there will be metric for just how many add_to_cart events there were, as well as its session and user conversion rate. We’ve found this to be one of the most useful metrics in GA4 especially since it’s now also available in Looker Studio, you just need to refresh the fields when you add a new key event.