How does internal linking optimization reduce click depth?

Short answer: Click depth is the number of clicks from the homepage to a page; internal linking reduces it by building shortcuts. The more deep pages are connected to hub pages, contextual blocks and navigation elements, the easier crawlers and users reach them.

Patterns that reduce depth

• Hub and cluster structure: the pillar page links directly to every subpage in the cluster; subpages link to each other and back to the hub.
• Contextual blocks: related links at the end of each page shorten vertical digging.
• Curation over pure pagination: important deep pages get direct links from the first category page or from index-style directory pages.
• Breadcrumbs: show the hierarchy to users and, via schema, to machines.

How to measure

Use a crawler (such as Screaming Frog) to extract the depth distribution and track the depth of target pages; after the change, compare crawl frequency and impressions in Search Console against the baseline.