So far, it is not possible to compare multi-keyword positioning (ranking) results in google or yahoo. Positions are not additive, because every keyword has a different difficulty. Obviously, it is better to be 1st of 100 than 1st of 10.
However, is it better 1st of 100 or 2nd of 1000? How about any other non-obvious pair of rankings?
Moreover, things get complicated when there are more variables: in addition to position (rank) and total number of SERP (search engine result pages), the search engine and the specific keyword.
The ideal measure of search engine positioning should have these properties:
– easy to calculate
– representative of the difficutly and merit of the positioning
– correlate with commercial results for the ranked site
– reflect the habits of the search public
It is known that most people search Google or Yahoo for the first 5-6 results. However, to cover the whole population, we need an idea of the math explaining this behavior, like an asymmetic Poisson distribution curve.
When several SEO companies want to compete, they create a contest with a single keyword or keyphrase: ‘mangeur de cicogne’, ultramarine nigritude and other nonsensical, unique, rarely sought phrases. This method is cumbersome, takes time, and otherwise useless. And it is completely separated from real life situations.
It would be much better to have a method to compare existing positioning results.
Thus, I proposed the SEPI, Search Engine Positioning Index, as:
SEPI = Total SERP x Keyword Difficulty ^2 / Position ^2
Keyword Difficulty can be estimated by the PageRank of the tenth page for a Google search on the keyword.
You can use this online calculator
This index is useful for:
– comparing results of SEO software or SEO campaigns
– comparing SEO companies.
– charging customers by SEO results
– measuring the effectivity of tools and techniques, applied to the same or different web sites.
We need consensus from the SEO webmaster community, or suggestions to improve this index.