Category-level conversion events, and the seasonal buying you cannot currently bid on

A category is usually a better predictor of what somebody will do next than the individual product they bought. Someone who buys skincare behaves differently from someone who buys a one-off gift, even if both spent the same amount on the same day.

What a per-category event lets you do

• Optimise a campaign toward a category with a high repeat rate, where the first order is worth far more than it looks.
• Bid harder in a category's season and step back out of it, without rebuilding the campaign each time.
• Separate gift buying from self buying, which are different people with different lifetime value even when the basket is identical.
• Suppress prospecting to people who already bought in a category recently, while still reaching them for others.

The repeat-rate case

This is the one most stores are leaving on the table. If one category reorders every six weeks and another almost never does, a first purchase in the first category is worth several times a first purchase in the second - and your ad platform has no way to know that unless you tell it. A category event with a value that reflects expected repeat, not just the basket, is how you tell it.

Where categories come from

Line items carry a category most of the time, and where a line arrives without one it is learned from your catalogue and your own order history rather than discarded. That matters, because a category event that silently skips a third of your orders is worse than no event - it produces a confident number built on a partial list.

What to do next

Pull repeat rate by category for the last year. Any category more than about twice your store average deserves its own event before you touch anything else.