Discrepancy between two unique events in Google Analytics

Question

Can someone explain why there is discrepancy in Google Analytics between two unique events, that are sent consecutively?

I have configurered onClick tracking on a button. When this button is clicked, an event (Event 1) is sent to Google Analytics and a CSS-selector gets visible on the page. When the CSS-selector is visible another event (Event 2) is sent to Google Analytics.

Both events have different event category, event action and event label. Both events are configured separately through Google Tag Manager with the same options for both tag and trigger.

When I look into Google Analytics Event 1 has always more unique events than Event 2. How come?

Answer 1

Is it possible that event 1 that fires on click is firing multiple times while the visibility event is only firing once? If the user is double clicking the button, two events will send. You should be able to configure the event in GTM to only fire once per page.

Answer 2

Not enough to go on, so here's an other stab in the dark - "visibility" actually means that the element needs to be in the viewport, not just that its CSS properties are set to make it visible somewhere in the page. So if for users with small screens (or just minimised windows) the element is not within the viewport it would not fire for them, resulting in less events. One mitigating step might be to set the "Minimum Percent Visible" setting to 1% (smallest valid value) to make it more likely that the trigger is fired.

A more thorough solution would be to let the function that changes the visibility emit a custom event and use that in a trigger.