Don't off-the-shelf e-commerce packages send banner clicks?

Generally not. In 84% of the more than 1500 stores I measured, no promotion event reaches the dataLayer, and nearly all of those that do are Ticimax setups. The packages cover ecommerce events such as category views, product detail, add to cart and purchase; the promotion side stays out of scope. So for a homepage banner, both the event to send and the ID it carries are produced from scratch during the setup.

Is measurement possible if banners have no id or data attribute?

Yes. The slide itself generally carries no ID field, but three sources exist in almost every setup: the URL the banner links to, the file name of the banner image and the ID of the slider container. Used as a chain, these three produce a distinguishing ID for each slide in the large majority of the stores I examined.

Why is it wrong to take slide order from the DOM index?

When a slider runs in infinite loop mode, the library adds copies of the first and last slides to the sequence. These copies are indistinguishable from real slides in the DOM; only their class carries a marker that says they are copies. If the count ignores that marker, both the total slide count and the individual position numbers shift, and the error is silent: the report looks full, the numbers are wrong.

Which platforms do the rates here come from?

The rates were measured on stores listed on the reference pages of T-Soft, Ticimax and IdeaSoft. The method itself does not depend on the platform; on Shopify, markup varies more from store to store because of theme flexibility.

Does this measurement show that a banner caused a sale?

No. What it yields is association, not cause. A causal claim needs different creatives rotated in the same slot, or a period in which the banner is not shown at all.

Deriving ID and Slot for E-Commerce Homepage Banners

Homepage banners go unmeasured in most e-commerce setups, because platforms send no promotion event and banners carry no field that holds an ID. This post covers how the ID and the position number are derived from markup, why slider copies break the position number, and at which point in a setup this measurement starts to pay off.

2026-09-05 Updated: 2026-10-14

TL;DR

Homepage banners go unmeasured in most e-commerce setups: the platform sends no promotion event and slides carry no ID field. The ID can be derived from the banner's target URL and image file name. The fragile part is the position number, because the slider library adds copy slides to the DOM, and a count that keeps them is wrong in at least 13% to 35% of setups across the three platforms I measured.

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