Using LSI Keywords to Improve SEO Ranking & Boost Organic Traffic

When was the last time you sat down to write an amazing piece of content, pulled out your mathematical matrix for determining the most valuable keyword phrases, and set to work with a smile on your face? Yeah, me neither.

If SEO and content marketers were forced to use a mathematical model to discover valuable keywords, our jobs would be a hundred times harder than they are now. Thankfully, there’s a little thing called latent semantic indexing (LSI) which can take your SEO ranking game from “0” to “100” in a jiffy (more like “100” to “1” if we’re getting technical).

To boost the results of your SEO strategy, you first need to understand how LSI works:

LSI is a mathematical method that identifies patterns in the relationships between concepts and terms in textual content and indexes the information for accurate recovery.

LSI has three main benefits that make it one of the most effective tools for improving SEO performance:

  1. Exceptional organic traffic potential
  2. The user experience is placed front and center
  3. It identifies the most valuable keyword terms and phrases

Understanding LSI is a requirement for modern SEO professionals and content marketers. It is no longer good enough to know how to create good meta descriptions, PPC campaigns, and keyword targeting strategies. Your SEO strategy needs to mirror the sophistication of Google’s ever-evolving search engine algorithm.

That means constant evolution is mandatory. Improvement begins with mastering the elements of LSI.

Latent Semantic Indexing 101

I’ll be honest. When I first heard the term Latent Semantic Indexing my initial reaction was something along the lines of, “How about them Yankees?” LSI isn’t a subject that’s easy to grasp from the bare-bones definition, so here’s a more practical description:

Latent Semantic Indexing is an algorithm that helps search engines understand the content on a web page and accurately compares and matches it with the searcher’s intent.

LSI helps search engines identify the most accurate results possible to match with individual search queries. It provides a detailed method for search engines to dig deeper into the connection between context and language.

How LSI Works

The LSI algorithm reviews the semantic relationship of documents using cosine similarities, vectors, and a bunch of other complicating terms I’d rather not add to the discussion. Fortunately, we don’t need to go down that rabbit hole. We just need to examine semantic relationships as they pertain to SEO ranking.

The semantic relationships of documents are categorized two ways by LSI:

  • Semantically close – when documents contain a large variety of similar words
  • Semantically distant – when documents have very few similar words

To determine whether two documents are semantically close or semantically distant, the algorithm analyzes patterns that decipher the context of words. Three different types of word patterns are inspected:

  1. Phrase correlations and associations
  2. Similarities and synonyms
  3. Volume of similar phrases or synonyms

Based on these three pattern types, the algorithm calculates similarity values (created for all content words), assigns a value to the document, and retrieves the document that most accurately satisfies the search query.

The more words in common a document has with a search query, and the more accurately each pattern deciphers word context, the higher relevancy LSI assigns to that document or web page.

It’s interesting to note that LSI works in a very similar way to the human brain, just without the ability to understand the meaning of words. Our minds consider the meaning of the words we read, write, and hear, and then use associations, similarities, and synonyms to determine the correct context.

We know, for example, that when our best friend says, “I hate you” in response to us getting a huge promotion, they are only teasing us. To reach this conclusion we interpret body language, tone, and past communications we’ve had with that friend.

A Mathematical Method

I am by no means a math whiz. At the first sign of an algorithmic equation, my immediate instinct is to turn tail and run. However, there are elements to the LSI algorithm that are too interesting to ignore.

LSI is a completely mathematical method of determining the accuracy of retrieved content to match a search query, that much we know. But which algorithmic elements does it use to accomplish this?

There are two aspects to the LSI algorithm that allow you to capitalize on SEO ranking potential:

  1. Natural language processing – An area of research that analyzes the relationship between human languages and computers. Natural language processing includes the distributional hypothesis (AKA distributional semantics), an area of research that focuses on quantifying and classifying language similarities. In practice, this hypothesis helps search engines calculate which words and phrases tend to have similar meanings by examining the words and phrases they are most often associated with.
  2. Singular value decomposition (SVD) – “A factorization of a real or complex matrix.” SVD is a fully automated method that studies patterns found in the relationship between terms and concepts. These patterns are identified in unstructured collections of text. Basically, LSI uses SVD to recognize which information should be retrieved.

Because LSI is mathematical we know that it relies on configurations. All you need to do is optimize your content to mimic those patterns and that’s where natural language processing and singular value decomposition come into play:

  • Create threads of similarity throughout your content by distributing common phrases, words, synonyms, associations, and terms in your copy.
  • Cater to SVD by creating a clear theme for your content that uses appropriate word and phrase correlations.

If you enjoy confusing the heck out of yourself, or actually enjoy math (God love you), feel free to dig into all the mathematical details, courtesy of Stanford.

The Relationship Between Terms and Concepts

This is where things can get tricky for LSI. It’s difficult for an algorithm to pick up on sarcasm, jokes, and innuendo that might change the context of a word, term or an entire document.

Read this phrase as an example:

It’s an expression with many possible interpretations. The speaker could be referencing a friend’s painful past and sincerely wants to know if they are alright now. The speaker could also be in the middle of an argument, directing this phrase at someone to make them feel bad about a decision. It all depends on the context.

LSI deduces the context of a term or concept and then helps search engines understand that when a parent searches for “binkie” they’re looking for a “pacifier.” The more context that’s included in a document, the greater chance it has of being retrieved and improving its ranking.

What’s the difference between a term and a concept?

  • Term: A word or phrase used in relation to a particular subject.
  • Concept: Something conceived in the mind.

Let’s look at some examples of each:

  • Term: “Mountain lion” is a term because it has a precise meaning and refers to a specific subject; a Puma or large feline.
  • Concept: “Love” is a concept because it describes something intangible that doesn’t have a single definition. If you asked 100 different people to describe love, you would receive 100 different explanations.

LSI uses the relationship between terms and concepts to establish a connection with related words and phrases. This allows the algorithm to extrapolate a perspective for each document.

What does this mean for your SEO strategy?

You can choose targeted keyword phrases used by established, high-authority competitors and still outrank them with an effective LSI-SEO strategy. How? By focusing on building definitive context into your content that delivers the most accurate, valuable results to search queries.

The Science Behind Crawling Webpage Content

Search engines crawl websites using bots that follow and examine all the links and pages on your site. Once a site has been crawled, the search engine indexes it along with information on keyword phrases and their locations.

When LSI goes to retrieve a document to match with a query, it goes through the search engine’s indexed pages to find the best match.

Make it as easy as possible for search engines to crawl your content, retrieve it for queries, and boost your ranking. The best way to do this is by implementing the elements of LSI into your SEO strategy; create targeted content with high-relevancy that aims to satisfy specific queries.

Tips for improving the crawlability of your content:

  • Create a list of keywords and keyword phrases closely related to your main keyword phrase
  • Distribute terms naturally (meaning don’t resort to keyword stuffing) throughout your content to provide easy, accurate context
  • Use synonyms and similar terms (where they add value)
  • Make sure there’s an ordinary ratio of common phrases, synonyms, keywords, and word associations in your content – don’t overdo it or you’ll end up damaging your ranking possibilities

Adding Context to Your SEO Strategy

LSI was created as a direct response to bad SEO practices, such as keyword stuffing. Years ago, all you had to do for a favorable ranking was cram as many keywords as possible into every nook and cranny of your website.

The game has changed drastically since those dark days. Today, SEO is a complex, ever-changing process that requires us to learn new concepts, master new skills, and modify old practices.

Amending your SEO strategy to account for LSI will help your site climb in search engine rankings while attracting far more organic traffic. Believe it or not, it is possible to give your site a significant boost in a short period of time.

Here are two LSI methods that will give your site the most immediate wins:

  • Structuring web copy
  • Using LSI keywords

1. Structuring Web Copy

LSI places a heavy emphasis on the quality and organization of your web copy. Everything from your H1 tags to the grammar of your body content impacts search engine rankings. Headlines should match the context of the H1 tag and the main portion of your copy should focus on establishing relevancy.

Structure the body of your content for SEO success by understanding how each component will affect your ranking. As usual, there’s a lengthy list of items you can optimize, but here are the two that carry the most significance and offer immediate wins:

  • Bolded and italicized words carry greater importance
  • Using keyword synonyms will increase page relevance and content value

2. Using LSI Keywords

Incorporating LSI keywords and phrases into your web content is essential to boosting the effectiveness of your SEO strategy. There are two main types of LSI keywords:

  • Keyword synonyms – Jog: dash, run, race, sprint
  • Related words and phrases – Jog: runners, Boston marathon, forms of exercise, cardio routines

Finding LSI keywords isn’t as difficult as many people think. I like to start with a simple Google search and then branch out into other methods.

Here are three of the best ways to find LSI keywords:

1. Google search

Enter your desired keyword in Google.

Scroll to the bottom of the search results and you’ll see a group of related search terms. These keyword terms specify some of the phrases and words that Google is already associating with your targeted keywords.

Conducting a Google search provides a quick, easy win for your LSI keyword research.

2. Google Keyword Planner

Perhaps the best method of all, the Google Keyword Planner tool makes finding LSI keywords and phrases a virtual breeze.

First, navigate to your Google AdWords account and log in. Then, click the stacked dot icon to open the drop-down menu:

Click on “Keyword Planner” in the far left of the drop-down menu.

Click on “Search for new keywords using a phrase, website or category”.

Enter your chosen keyword in the “Your product or service” text box, and hit the “Get ideas” button.

You’ll instantly have access to a massive list of related keyword phrases, all of which Google associates with your original search term.

3. SEMRush

SEMRush offers a variety of great options for finding valuable keywords and keyword phrases, but the best one is their “Keyword Research” tool. Start by entering your chosen keyword in the search bar and clicking “Try It”:

A results page will load, displaying similar phrases, keywords, and keyword metrics. Find the “Phrase Match Keywords” section and click “View full report”:

Once you’ve opened the full report you will have access to thousands of related keyword phrases which can be used to bolster the relevancy of your content:

Because the nature of LSI is to retrieve only the most accurate documents, content that does not follow best practices will be penalized for lack of context, value, and quality. Even worse, the ranking for sites that use antiquated black hat SEO techniques will plummet (hello page 5 in Google results).

LSI red flag practices to avoid:

  • Filling meta keyword tags with hundreds of keywords
  • Stuffing meta descriptions with keywords
  • Sprinkling page content with random, useless keywords
  • Failing to create subject matter content that adds value or context
  • Using unrelated keywords
  • Switching the entire contents of a page after it has already been indexed

The Final Touch of Context

There’s one final way to increase the accuracy of your context; choose a theme for your content that’s supported by LSI keywords and stick to it.

Everything needs to make sense to the search engines. If your content is focused on “jogging” and you suddenly throw in a paragraph about “windsurfing,” it needs to be relevant and somehow tie into your main theme.

One final reminder on context; choose a natural placement for your keyword phrases. Try to organize LSI keywords the same way people speak in a face-to-face conversation. Forget about useless rules, like including a minimum of one keyword per paragraph. Instead, focus on the quality and flow of your content.

The Benefits of LSI

Latent semantic indexing is not new to the search engine world by any means, but it has taken a back seat to more mainstream tactics. Because of this, relatively few people understand how to optimize their content for LSI. That’s a good thing. It means those who take the time to comprehend and implement LSI tactics will be leading the SEO charge.

If you’re not yet convinced that LSI is one of the best methods for enhancing your SEO strategy, check out this extensive list of the benefits associated with LSI:

  • Modifies the indexing process to improve the way documents look to search engines
  • Sites that utilize LSI keywords are rewarded with more organic traffic and higher ranking
  • Increases revenue potential
  • Blocks attempts to mark your content as spam
  • Makes it easier for search engines to match queries with accurate results by providing relevancy based on content structure and semantics
  • Delivers content to searchers faster
  • Increases the time visitors spend on your web pages
  • Improves the authority of your blog and overall website
  • Reduces website bounce rates
  • Provides a method for understanding the relationship between words, phrases, and terms that generate targeted organic traffic

Mastering the principles of LSI is simple. It’s all about adding context and making all aspects of content relevant.

If you’re writing about roasted peanuts, your page title better include something about roasted peanuts. If your keyword phrase is “bag of roasted peanuts,” there needs to be a distribution of synonyms, related terms, and phrases that are geared toward natural language processing.

LSI isn’t rocket science, it’s just science. Incorporate LSI features into your SEO strategy and you’ll start seeing an uptick in organic traffic and a rise in your search engine rankings.