How the ranking works
Under Meta’s Aggregated Event Measurement framework, a verified domain configures a short list of web events and puts them in order. When a visitor who has opted out of cross-app tracking triggers more than one of those events, Meta does not report them all. It reports the one you ranked highest and discards the rest for that session.
So a shopper who views a product, adds it to the basket, starts checkout and then buys has produced four configured events. If purchase sits at the top, purchase is what gets reported. If add to cart sits above it, add to cart is what gets reported — and the sale, from Meta’s point of view, does not appear.
The order is set once, at domain level, in Events Manager. It applies to every ad account advertising that site.
Why the order matters
Ranking is not a reporting preference; it decides what your campaigns can learn from. Delivery optimises towards the event it is told about, so an account whose most valuable outcome sits low in the list will be taught to find people who take a cheaper action instead. Cost per lead may even improve while revenue falls, because the machine is now buying exactly what you accidentally asked for.
It also shapes what a client sees. A business whose sales are underreported because a softer event outranks the purchase will conclude that the advertising does not work, and cut budget on the strength of a configuration mistake.
Where the ranking goes wrong
The most frequent fault is ordering the list by the order events happen in the journey rather than by value. A funnel reads naturally from view, to cart, to checkout, to purchase — and typed into the configuration screen in that direction it produces exactly the wrong result.
The second is leaving an old test event at the top. Someone adds a temporary signal to debug a form, ranks it high so it is easy to see, and never moves it back.
The third is reordering the list often. Every change disturbs how campaigns learn, so an account whose ranking is adjusted every few weeks never settles.
How to get the order right
Rank by commercial value, highest first, ignoring the sequence of the customer journey entirely. For a shop that means purchase at the top, then checkout started, then add to cart. For a service business it means the qualified enquiry above the general contact form, and the general contact form above a brochure download.
Where several actions are genuinely worth different amounts, consider whether one event carrying a value parameter would serve better than several separate slots. Agree the ranking with everyone who advertises the domain, record it outside Meta, and change it only when the business changes — then leave it long enough for campaigns to settle. Sending events through both the pixel and the Conversions API will not raise the limit, but it improves how much of your ranked activity reaches Meta in the first place.