is your keyword competitive?

how do you define the comptetition rate by considering & comparing the total number of results returned by google.

Google returns 767,000 results for search engine optimization.

Google returns 132,000 results for search engine optimisation.

Can we simply conclude that roughly, search engine optimization is 6 times more competitive than search engine optimisation?

I found this technique quite reasonable when I want to learn how comptetitive is the market for certain keywords.

I don't look at it like that, each SERP is an 'instance' of the keyword/phrase in a file, not necessarily a competitor.

Here's how I gauge competition:

1) Search for domain names, if you can't find a decent selection of two and three word phrases separated by '-' then you may have some heavy comp.

2) Search Google for industry specific phrases, if you see the above style domain names i.e. "we-match-single-people(.)com" in the top 20 then you have your hands full. - note: scan Adwords for hints to comp.

3)This by far the easiest step...go to Overture, type your phrases...anything over one dollar and you've probably got some people happy to show you up.