Category taxonomy

Category taxonomy decides which products shoppers see together before filtering or sorting begins. The business outcome is a catalog that supports broad exploration, focused browsing, and comparison without sending shoppers through unnecessary layers.

This module covers the boundary between categories and attributes, the depth of the tree, the role of sub-subcategories, and how long navigation sets are grouped. These decisions belong together because every new category changes product scope and every new level changes how much of the catalog a shopper can compare. Baymard’s research found problems when shared product attributes were turned into separate categories, and supports using filters to narrow one comparable list instead.¹

Work from products outward. Define the distinct product groups first. Then decide which attributes narrow those groups, where an intermediary page adds real choice support, and how the remaining branches should appear in navigation. Do not begin by drawing a symmetrical tree.

Module diagnostic

Select one deep branch and export or manually list the products under every final category. Mark product overlap, shared comparison attributes, tiny or empty destinations, labels with internal jargon, and steps that do not materially change scope. Then ask whether a shopper can view all reasonable alternatives together.

Small assignment

Choose one false split or unnecessary level. Draft the proposed parent scope, the product moves, the filter that replaces any attribute category, redirects required for existing URLs, and the revised menu grouping. Assign catalog, SEO, navigation, and theme owners where they differ.

Evidence and further reading

1. [1]“Overcategorization of the Product Catalog Can Lead to Abandonment,” Baymard Institute, https://baymard.com/blog/ecommerce-over-categorization. Supports keeping products with shared attributes in one list and using filters for narrowing. Accessed August 23, 2026.