Keyword Efficiency Index

How to determine low hanging fruit keywords to target first by using KEI





What is KEI? 

KEI, which stands for Keyword Efficiency Index, is a metric used in Search Engine Optimization (SEO) to evaluate the potential value of a keyword. It helps determine how effective a keyword is by considering its search volume and competition level. Calculating KEI involves a simple formula, which I’ll explain in detail below.

You can find different formulas to find KEI but here is explained the real and easiest formula to get the real KEI value to determine the keywords. 

In general, it is the ratio between search volume and some competition metric or keyword difficulty metric. It is often expressed as a fraction where:

KEI = Search Volume / Competition 

Keywords with a higher KEI help you prioritize the keywords you would want to target first because you are getting the best balance between keywords that are searched the most with the least amount of competition.

The original formula for KEI, when it was first mentioned online by Sumantra Roi who created this for one of the pioneer keyword research software WordTracker, was:

KEI = (P^2/C)*1000

In his formula, P was the popularity of the keyword which is essentially Search Volume, and C was the competition metric, where Roi used the number of search results.

Breaking this formula down, it is still search volume over competition. And since the search volume is in the numerator of the fraction, it is directly proportional to KEI, while the competition is in the denominator which is inversely proportional to KEI.

This simply means as search volume increases, KEI increases. And as competition decreases, KEI still increases.

Roi’s original formula squares the search volume, and then multiplies everything by 1000 to adjust the number to make it more “readable.” This avoids getting values that are lower than 1 with many decimal places.

You can also use your own formula, as long as the search volume is in the numerator and competition metric is in the denominator. Assuming the latter is followed, you can then multiply any factor to it to make the number more readable to people that may use your formula.

Here are steps to find out the KEI value: 

Step 1- 

Finding the search volume of the keywords. There many tools to get the search volume. Here we have used SEMRush but you can also use “keyword surfer” Chrome extension or other tools for finding the search volume. 

Step 2- export the keyword research details 

Step 3- Keep only search volume and search result data in the sheet. Apply the basic formula which is “Search volume/search results”

One thing you will notice is that most of the KEI values are below zero, and some are using scientific notation. Look at the second keyword as it has a KEI of 5.7508E-05, which means 5.75 x 10-5 or 0.000000575.

Since it is hard to read which numbers are higher or smaller, it makes sense to me why Roi squared the search volume to make it a larger number, moving it further away from the Number of Results metric that can sometimes reach into the millions. To shift the decimal place 3 digits to the left, he multiplied it by 1,000. Applying this in the spreadsheet you get this:

Step 4- 

Apply the formula:

=IFERROR(((B2^2) /C2) *1000, 0) 

Where B2 means the search volume column and C2 means the search results column

From here, you can replace the number of results (column F in this example) with any of the other competition metrics (columns C to F). And when you do that, you will see, you do not always need to square the search volume and/or multiply it by 1,000. Which is why I don’t apply ROI’s KEI formula, and I simply divide search volume by the competition metric of my choice. But to make it easier to read, I will use Excel’s RANK formula to rank all of these to find the top KEI to lowest KEI. 

Step 5- 

Use the below formula:


Where D2 means KEI column and 15 represents the number of rows, it will depends on number of keywords. 

Here we can see the the “Top KEI” Values in F column. 

When KEI is low, it can mean 3 things:

1.Search volume is very low.

2.Competition or keyword difficulty is very high.

3.Both search volume is low and competition is high.
So we should choose the higher Top KEI value for selecting the low hanging fruit keywords to target first.