The Keyword Effectiveness Index, also called KEI, is one way to predict the chances for successful high rankings. KEI is a relative factor that compares targeted keyword phrases to the number of pages competing for these phrases. The results are stack-ranked based upon the chances for success. The higher the KEI factor, the easier (theoretically) it should be to obtain higher rank positions and targeted traffic for the given phrase. The ideal is to find keyword phrases that are searched for often, but have relatively little competition from other web sites.
KEI compares the search popularity, or number of times that users search using a specific phrase, to the number of web pages competing for that phrase. The results are always relative to one another, so you can use any two sources that you wish. The formula for calculating KEI is simply to square the search popularity for a phrase and divide it by the number of competing pages.
In algebraic form the formula looks like this:
(Search Popularity x Search Popularity) / Number of Competing Pages
The Search Popularity factor can be derived from the Google AdWords Keyword Tool. This tool provides an estimate for the number of times a keyword phrase was used in a Google search during the previous month by USA users. It is important to use the Phrase Match option (checkboxes in left column) when displaying the AdWords Keyword data. The Number or Competing pages is taken from Google search results. Perform a search in Google using a keyword phrase, but surround the phrase with double quotes. This performs a phrase match search and will return the number of web page in Google’s index that use that exact phrase somewhere on the page.
WordTracker is a popular paid subscription keyword tool that provides estimates for the number of times a keyword phrase was used in a search on average, per day, over the previous 90 days. It uses data compiled Dogpile, Metacrawler and other smaller search engines. The demographics of the users tends to be different with these search engines.
If you wish to compare WordTracker’s results with Google’s, there is a free version that anyone can use. This tool reports the estimates for daily searches, plus it provides a list of related search phrases. The only issue I see with using WordTracker information is that it does not use search data from any of the major search engines.
The freebie WordTracker Keyword Suggestion Tool is found at:
Personally, I think that Google’s keyword results are more relevant, especially when they are compared to the number of competing sites found in Google’s index.
Does a high KEI guarantee good results? Absolutely not. It is just one way to look at the data. It can be very useful when determining which keyword phrases should be prioritized in an SEO campaign and should be a part of keyword research. Any search phrase that has an overwhelming number of competing pages will always be difficult to compete with, regardless of what the KEI indicates. There are over 200 factors used by Google to determine how a web page will rank against all others competing for a specific search phrase.