Google Patent US8924380B1 provides the definitive answer to this frequently asked question. The patent explicitly states: "it might take approximately 70 days for a change in a document's link-based information to change the rank of the document to its steady state (target) value."
This 70-day timeline (approximately 2.3 months) from Google's own patent documentation explains why experienced SEO professionals have long recommended waiting at least 3 months to evaluate the success of optimization efforts. It's not just industry best practice—it's literally how Google's ranking system is engineered to work.
The patent describes this extended timeline as part of Google's "rank transition function," which "varies the transition rank over time without any change in ranking factors associated with the document." During this 70-day period, your website's rankings may fluctuate unpredictably, not because your site quality is changing, but because Google is intentionally applying time-based variations to observe how you respond.
The patent also reveals that for some changes, rankings might initially decrease for "approximately 20 days before settling in on its new steady state (target) value." This means the full process from initial ranking drop to final improved position could take up to 90 days, perfectly aligning with the traditional "3-month rule" in SEO.
Understanding this timeline helps home service business owners set realistic expectations and avoid making panicked changes during the transition period, which Google's system specifically monitors as a sign of potential spam manipulation.