A page’s rankings can be influenced by other pages on the same website. How big the influence of these pages is depends on their importance.
In the question of whether Google only calculates the rankings for individual pages, or whether the surrounding website also plays a role, there was now another interesting clue. In the Google Search Central SEO Office Hours of February 5, the question was asked whether Google would rate each page individually, or whether, for example, a poor rating of a domain’s homepage could have an impact on the other pages.
John Müller said that Google tries to evaluate as small as possible and to concentrate on individual pages. However, there are links on a website and thus connections between the individual pages. If a page is very bad and it is the most important page on the site, then that will definitely have an effect on the other pages because they are in the context of the main page. On the other hand, if any page on a website isn’t that high quality, then that usually doesn’t pose a problem.
How does Google evaluate which pages of a website are central and thus have a major effect on the other pages? Linking certainly plays a role here. Both internal links and external links should be included in the rating. Because the home page is usually the best internally linked page on a website, it occupies a central position.
In practice, this means: Particular attention should be paid to the quality of central pages of a website such as the homepage and category pages. This also applies to all other pages that could be considered important for a website by Google due to their internal and external links.
However, the decision about which are the most important pages of a website should not be made from this perspective alone. It is also important, for example, how many visitors there are on the various pages and which pages make the greatest contribution to the success of the website, for example by generating sales.