A lot of retailers allow for multiple related items (variations) to be sold from a single product detail page (PDP). Analytic Index focuses on search results pages and category pages that drive traffic to the PDP where these variations are found
Analytic Index currently doesn't capture item variations as we focus on the search results and category pages with lists of items that the retailer surfaces as the performance items. The retailer algorithm surfaces a particular link to a product detail page in a search result slot which allows for Analytic Index to be agnostic to the variations found on the product detail page.
For example: a purple T-shirt size 7 is the top selling item of a group of items we will capture whichever item retailer surfaces in the search results based on the retailer's search algorithm.
This works because Analytic Index isn't looking at the search rank of individual items that share a PDP. We are capturing what the shopper experience is for a given search term or category and the shopper will only see one version of the item in these search results (this is the item we capture) and the shopper will click through and make their purchase decision based on the variation choices on the PDP.
From the retailer algorithm standpoint the algorithm is tuned to surface those items that are most relevant and convert the best for a given keyword. This means that all variations of a product an help contribute to that relevancy and conversion metric.
Additional information about variations at specific retailers can be found here: