Tiered link building boosts your website’s authority by using multiple layers...

https://lilysbestblog.theburnward.com/how-do-i-set-goals-for-a-link-building-campaign-without-guessing

Tiered link building boosts your website’s authority by using multiple layers of backlinks. Tier 1 links point directly to your site, while Tier 2 links support those Tier 1 sources