Competitor research is an analysis of a competing website within a client's industry. This may not be an obvious well known competitor, but is defined as a website that ranks highly for certain suitable keywords.

Google and the internet is basically a computer. So all things being equal if the top ranking website for your keyword has 10 links, 10 pages and an overall internet presence of a 100 other website mentions, if we simply replicate this pattern, then all things being equal, your website would rank in a similar position.
Unfortunately it is not always as simple as this, but competitor research does provide useful online marketing targets and milestones.
Example of Competitor Research