Is SERP Determined By Site or Page?

This has been a question of mine for quite some time? Is the position for keywords determined by site (domain) and the entire sites backlinks and on page optimization, or is the homepage on page SEO for my domain and the backlinks to it determine SERP. I'm guessing it's somewhat of a combination, as my homepage is pretty static however the site is continually having new content. All views appreciated.

 

I say serp results are based on each page and keywords and links

 

Anyone else with ideas. The reason I'm asking, is I have older html style sites, not blog and my content changes are primarily to additional pages in my site. My homepage only changes by having new links to those pages.

So, if the SERPs are only judged by content changes on my homepage, I guess I won't be doing to well. Anybody else with how SERP for content changes is really determined?

 

I think SERP determine by each contents, link and keywords.

 

Serp is deterimned by links, page and keywords

 

Keywords & links determine the serp position.