Keyword Effectiveness Index

Calculating the KEI for a Keyphrase

KEI - Keyword Effectiveness Index. This is a simple ratio that, while computed in different ways for different search campaigns, follows the general equation: 

• KEI = competition/ # searches.

You can use this to determine how competitive a given keyphrase will be. The lower your competition, and the higher the number of searches, the easier it will be for you to rank highly in the SERPs (Search Engine Results Pages) and attract relevant traffic for that particular keyphrase.

Keyword Effectiveness Index Calculation

You can use a Google search to identify your competition.

There are two different metrics you can use to help calculate your KEI. Some SEO'ers prefer one over the other. We'll be using them both, and we'll explain why. Using the box, search for a keyphrase you've identified using Google's Free Keyword Popularity Tool. It's important that you compare searches using the match type filter explained in that article. Why? Because you'll be able to filter searches down by phrase and exact match to get a better idea of precise search volume numbers.

Finding Search Volumes

Typically, we recommend that you use either "phrase" or [exact] keyword search volume data when calculating your KEI. With broad search volumes, it's more difficult to optimize a page based on the exact phrase a user is searching for.

Gauging Your Competition

In our example, we'll use "keyword effectiveness index." There are two ways to search this phrase; the first, with quotes; and the second, without. We'll show you both ways and the difference between each. 

1. Search with quotes - let's say you're trying to rank highly for the key phrase keyword effectiveness index. If we search for this term in quotes - ie. ""keyword effectiveness index", we see that (at the time of writing), 10,800 pages contain this phrase. This doesn't necessarily mean you're going up against 10,800 competitors for this keyphrase. It simply means that's how many pages contains this exact combination of keywords.
2. Search without quotes - the second search you'll want to do is without quotes. So, in our example, we search for keyword effectiveness index (without quotes) in the Google search box. In this instance, there are 192,000 results. This also doesn't necessarily mean that you are competing against 192,000 websites - it simply means that Google returned 192,000 pages for which this keyphrase is indexed. In some instances, multiple pages will belong to one website - although Google algorithms have been hard at work at trying to bring up only the most representative page, from each website, for a particular keyphrase.

Calculating Your KEI - now that we have our two results, we typically place these in columns in a spreadsheet to keep our analyses organized as follows:

KEI Formula

You'll see that the values we've come up with for KEI vary greatly. In this case, as far as KEI goes, running the keyphrase "keyword effectiveness index" results in the following Keyword Effectiveness Index values:

KEI¹ = S²/R = 720²/192,000 = 2.7

KEI² = S²/R" = 720²/10,800 = 48

KEI³ = S/(R/1000) = 720/192 = 3.75

KEI⁴ = S/(R"/1000) = 720/10.8 = 66.67

Where S² = # monthly searches squared, R = # results without quotes, R" = # of results with quotes.

KEI with Filter for High Competition Searches

We've come up with a preliminary fifth formula that still requires some testing. It's purpose is to provide a KEI value that attempts to filter out very high competition values (ie. if pages are super competitive, they may have a high KEI value given the ratio to search volume, but penetrating such stiff competition may still be too difficult). This KEI equation, therefore, targets the long tail end of searches (ie. results in a subset of keyword phrase candidates that offer low competition figures).

KEI⁵ = (S²/(R³/10⁶))*10⁴ = (720²/192,000³/10⁶)*10⁴ = 1

Which KEI Value Should I Use?

What's the difference between all these KEI's? KEI¹ uses the results with quotes, while KEI² uses the results without quotes. Many SEO'ers rely solely on KEI¹. However, from our real world analyses, we've found that the number of terms a keyphrase actually appears in pages isn't enough of an indicator to justify disregarding KEI² results. In particular, we've had examples where the results (competition) with quotes is very small, yet the phrase is very hard to rank for because it returns a high number of results without quotes. You'll also notice that for more general keywords (ie. "keyword" in our example), the results get blow out of proportion due to the logarithm. This is where KEI³ and KEI⁴ come into play. They take out the logarithmic effect and give us a linear KEI value. We divide the results without quotes by 1000 to give us relative numbers to work with (if we don't divide, the results all round out to zero).

Another thing to take into account, is that while it's useful to know how many times a specific keyphrase actually occurs, this doesn't reflect how people actually search. Most of the time, searchers search for phrases without quotes. It's only when they're narrowing down their search that they typically implement searches with quotes. In addition, when you're researching your competition for exact keyphrases (in quotes), you often find only parts of an entire keyphrase, and the resulting competition count can be misleading. For example, if you search for "how to optimize", you will find millions of results on pages that contain that phrase - yet no one searches for simply "how to optimize." The phrase is always followed by the item they are searching for how to make - ie. "how to optimize an email campaign," or "how to optimize a website for ad placement," etc. When analyzing your competition and using quotes, therefore, it's very important that you look at your keyphrase in the context that it is returned in the SERPs, and find out if it makes sense as far as your keyword campaign goes.

The Best Keyword Effectiveness Index Is...

Now, some SEO companies will average different KEI values together to get a final KEI value. To us, this doesn't make sense, since the calculations vary completely - the end result wouldn't reflect consistent competition figures relative to what people are searching for. Therefore, we typically draw a table, as illustrated above, and then bold the highest numbers in each column. At the end, we'll choose those contenders with the highest KEI values across the board for our short list.

Single vs. Multiple Keyword Results

You'll note that there are extremely high KEI values across the board for "keyword." While we added this word in as an example, we need to point out that results vary widely when you calculate a single keyword as opposed to a keyphrase (multiple keywords). If you think about it logically, most people search for "keyword" combined with other words. How many times have you simply plugged "keyword" into Google? Nevertheless, if you can be the #1 result for "keyword," you'll no doubt attract quite a bit of traffic, and if you're that good you probably don't need to be reading this

Rankings for "Keyword"

Interestingly, at the time of this writing, the #1 result for keyword was Google's Free Keyword Popularity Tool website. The #2 result is Wikipedia - a public encyclopedia contributed to by millions, and one of the highest trafficked websites on the Internet. The #3 result is WordTracker - a paid keyword research service which is quite useful if you really get into keyword research. But most interestingly is the #4 result, keyword.com. Why is this so interesting? Because Keyword.com has a measly 151 pages indexed in Google. Normally, such highly ranking websites have hundreds of thousands. Their business model is based on a unique idea - instead of returning search results, they take you directly to a page with the keyword you're looking for. But what we're getting at here is the importance of keywords in your domain name. It turns out it's much easier to rank highly for keywords if you already have them in your domain name. That's one reason the domain industry, and the domainers (people that buy domain names solely for their keywords), have become such a big thing over the past decade or so (and why it's so difficult to find a good .com domain name these days).

Evaluating Your Competition

An important thing to keep in mind is that the KEI should only be used as a way to narrow down your keyword list. Once you have your list narrowed down (to your short list) based on the highest KEI values, it's important that you do an individual evaluation of your first page competition.

Evaluating Your First Page Competitors

Once you've come up with some high KEI candidates (which you put on another spreadsheet, that we'll refer to as your short list), plug these keyphrases into Google to search for your competition. Just like you could search for your competition, for calculating your keyword effectiveness index, with and without quotes, you can do the same thing when evaluating your competition. The most important competitors are those on the first page, beginning with the number one result.

This is where you take the time to evaluate your competition in terms of all the search advantages we discuss throughout this website. Ie. - how does their page structure look? How many backlinks point to their website? What is their Alexa rank (indicator of how much traffic they get)? Etc. etc.

This will give you an idea not only of how difficult it might be to compete against them, but also may enlighten you as to techniques and methods you can use to help rank higher for your particular combination of keywords. 

Have fun calculating your KEI and evaluating your competitors! Once you've identified a niche, it's time to start writing content to target your keywords, and initiate your search marketing campaign so you can get ranked and increase the targeted, relevant traffic to your website.

Comment below with questions and comments!