What does Keyword Efficiency Index mean in SEO?
The Keyword Efficiency Index is a mathematical calculation to consider if it is worth trying to rank for a particular keyword or keyword phrase by weighing up its popularity versus how much competition there is for it. It is generally seen as a deeply flawed gimmick.
The Keyword Efficiency Index Formula
Monthly search volume2/Competition
The two parts can be gleamed from Google:
- Monthly search volume - the number of times a keyword phrase is searched every month. This can be found in Google's free to use keyword planner (within Google Ads)
- Competition - the number of results Google returns when the keyword is searched. You'll see this in the Search Engine Results Pages (SERPs), usually written as, for example, 'About 734,000,000 results'.
The theory says that the higher the KEI is for any keyword or phrase, the easier it is to rank for a page for that keyword or phrase.
"Keyword phrase A" is searched 2,000 times per month and Google returns 400,000 sites when "Keyword phrase A" is searched so the KEI is 10 (2,0002
"Keyword phrase B" is searched 3,000 times per month and Google returns 350,000 sites when "Keyword phrase B" is searched thus giving a KEI of 25.
You are meant to conclude that "keyword phrase B" will be easier to rank for because it has the higher KEI.
The KEI flaws
KEI is widely seen as a gimmick with little real use as it misses too many factors. In particular:
- Competition heat - while the formula might tell you how many websites are ranking for the keyword or phrase it doesn't show how fierce that competition is.
- Keyword profitability - many generic keyword phrases that are heavily searched are not actually profitable due to something known as the buying cycle. Once an Internet user has made a generic search like 'cars for sale' they then tend to use more accurate (and less generic) searches as they narrow down what they are actually looking for before making final purchases.
This means search volumes of any keyword or phrase and their competitiveness when it comes to ranking do not always correlate leaving the Keyword Efficiency Index as little more than a meaningless number.