LSI.

Sounds like a new term?

Keep on rolling.

Latent Semantic Indexing (LSI) is a part of the Google algorithm.

Knowing about it and implementing it as a part of your SEO strategy is crucial.

This post presents you the concept in an easily understandable way.

What are LSI keywords?

LSI keywords, also known as semantic keywords, are terms closely related to the main keyword. Search engines like Google use them to grasp the connections between different elements of web content and decipher the meaning of written text.

Incorporating LSI keywords alongside main keywords boosts SEO by improving search relevancy. This strategy evolved from earlier search engine methods that relied on exact match queries, which often led to inaccurate results.

The power of Latent Semantic Indexing lies in its ability to spot related words within a topic.

Let me put it in another way.

Ever pondered how search engines tell apart homonyms (words with multiple meanings)?🤔

You might have noticed that Google highlights synonyms in search results.

Let me take an example.

Search for “ps picture size”. Google highlights the words “Image, Photoshop”.

The term “PS” has different meanings in Google, like PlayStation, Photoshop, and so on.

Google returns results based on the keywords you use after the term “PS”. Here it understands that the term “ps” in this context refers to Photoshop because I’ve used “image size” after it.

By doing this, it can determine what the user is trying to search for. This is part of Google’s LSI algorithm.

Here’s the kicker.

Here, once I append the word “fps” to the “ps” keyword, Google easily discerns that I’m talking about either first-person-shooter games in PlayStation devices.

So when it comes to blog post SEO, it’s fair to say – “Google interprets the meaning of content by analyzing semantic keywords that appear alongside the main keyword and identifying relationships between them. “

No?

This means something:

By incorporating semantically related words or synonyms of the primary keyword in your articles or blog posts, you can potentially improve your search engine rankings.

This approach helps Google better understand your content’s context and subject matter. By incorporating related synonyms and semantic keywords alongside your main keyword, you can improve your content’s relevance and meaning in the eyes of say Google.

While this strategy can boost rankings, it’s important to note that using LSI keywords in your content alone isn’t enough – site authority and quality backlinks are also crucial factors in SEO success.

Is LSI keywords a ranking factor?

According to a tweet by John Mueller (a Google representative), in 2019 – Google doesn’t appear to use LSI keywords in their ranking algorithms.

Instead, based on my understanding, Google likely employs a more sophisticated approach.

This could involve techniques like TF-IDF (Term Frequency-Inverse Document Frequency) or perhaps even a variation of latent semantic indexing.

👉 However, recently LSI keywords and related keywords are used interchangeably. But these are not the same. Because the related keywords conventionally are related to the variations of the main target keyword.

What is Latent Semantic Indexing?

While Google has stated they don’t use LSI specifically, the concept of semantic search remains relevant.

Search engines analyze semantic relationships between different documents it needs to rank:

• Semantically close: Documents with many common synonyms, phrases, and related entities.
• Semantically distant: Documents with few common words or relationships.

This analysis helps search engines provide more relevant results to user queries.

So to improve your content’s semantic relevance (or relevance to a topic):

• Use related keywords and synonyms naturally in your content.
• Implement structured data to help search engines understand your page’s content and purpose.
• Focus on comprehensive topic/entities coverage rather than targeting specific keywords.

👉 In short, you need to optimize your content for a specific topic (doing topical optimization) than individual keywords.

How to find LSI keywords?

Google Search

When you’re writing a blog post on a specific topic, for example, AI for blogging, you need to search for the keyword on Google.

Then, observe the keywords that Google suggests as you type and the topics under the “People Also Ask” section.

These suggestions provide insights into:

• Related keywords Google associates with your topic
• Questions people commonly ask about the subject
• Topics you should cover to make your content more relevant

By including these elements, you can make your blog post more topically and semantically relevant to search engines.

Google Suggest Tools

You already know that Google presents the related keywords

In above example, I took “paleo diet” as my seed keyword. I searched for it in Google. Now Google presented me all LSI or related keywords to the main keyword.

But what if you want to take it to the next level?

There are various tools for this!

You can easily find the related keywords to your main keyword in Google Auto Suggest tool. You can insert asterisks (*) symbol to fill in the blanks the Google suggest.

You can also use UberSuggest or Soovle (quickest way to fetch all the suggests like Google, Yahoo, Wikipedia, Amazon, YouTube, etc.)

Google Search Console

Google Search Console displays you the keywords that are driving traffic to your site.

Here you can pick a popular blog post from your site.

In the above example, I have chosen a blog post titled “Top 20 Most Profitable Online Businesses.”

You’ll see all the keywords driving traffic or search impressions to that post.

These are terms you might not have originally planned to target.

If there are keywords you haven’t specifically optimized for, consider improving your post to rank better for these related keywords.

Analyze Competitor Content

Before writing, thoroughly research top-ranking competitors for your target keyword. Use tools like Smart TOC to examine their content structure and topics covered.

This reveals:

• Essential LSI keywords to include
• Important subtopics to address
• Potential gaps in existing content

By incorporating these insights, you’ll create more comprehensive, semantically-rich content that better satisfies user intent and improves your chances of ranking well.

Ultimate Keyword Hunter

It’s a unique LSI tool that I’ve ever used. It’s great.

This tool is only for Windows users. I hope they’ll also release a Mac version of this tool

Just head over to UltimateKeywordHunter, enter the email to help them send you a copy. Go to your inbox and click on the download link. The setup file is just around 2MB. Install it.

Enter the keyword for which you have to search for LSI keywords. Hit PARSE.

Wait for the analysis to complete, and hit analysis report.

The result will be opened. Basically, this report contains the most repeated semantic terms in Google top 10 results for the seed keyword. In the result, the stop words are excluded. So you will get rock solid semantic keywords.

The semantic keywords in the result are grouped as 1 word, 2 words, 3 words, 4 words…

You can export the LSI keywords in the result as CSV file, and upload it in the Keyword Planner for search volumes and effectiveness, if you are really paranoid.

Premium tools

To enhance your LSI keyword research, you can make use of premium tools like SEMrush, Ahrefs, and Serpstat. These tools offer advanced features that can significantly improve your keyword analysis and content optimization efforts.

Let’s start with SEMrush. This versatile platform is not just a competitor keyword and backlink research tool, but it also excels in finding related keywords. After entering your seed keyword in the search bar, SEMrush presents you with a wealth of data, including search volume, CPC, and competitive metrics. What sets it apart is its “Related Keywords” and “Related Phrases” reports.

The beauty of SEMrush lies in its ability to display search volume and CPC for these related LSI keywords, giving you a clear picture of their potential. While the complete report requires a pro plan, the insights gained can be invaluable for your SEO strategy.

Moving on to Ahrefs, this tool offers a unique approach to finding LSI keywords. Here’s a strategy I frequently employ: after identifying a target keyword for a blog post, I search for it on Google and note the top 3 ranking pages. Then, I use Ahrefs to uncover all the related keywords driving traffic to these top-ranking pages.

For instance, if a site ranks well for “best turntables under $100”, Ahrefs might reveal that it also ranks for variations like “best record player under 100”, “best budget turntable”, or “top turntables under $100”. These variations are often LSI keywords, providing you with a goldmine of semantic relevance.

Lastly, let’s explore Serpstat. This SEO tool offers three powerful features for finding LSI keywords: related keywords, search suggestions, and search questions. The related keywords report shows terms semantically linked to your primary keyword, while search suggestions reveal popular queries that appear as you type. Search questions, on the other hand, present interrogative forms of these suggestions, helping you address user intent more comprehensively.

By leveraging these premium tools, you can gain a deeper understanding of the semantic landscape surrounding your target keywords, allowing you to create more comprehensive and relevant content that satisfies both search engines and users.

Other tools

These Related keywords are also called Related LSI Keywords (rLSI). Apart from Google search, you can also use the Google Keyword Planner. The goal is to note all the synonyms to your main focus keyword.

Another tool that you may consider using to do the LSI keyword research is the best visual keyword research tool called – AnswerThePublic.

It helps you easily make out relations with various entities and come up with less competitive LSI keywords you can target.

You can also make use of a tool called LSIGraph. This is a tool that’s specially meant for LSI keywords research. Although there are many such tools, the fact that this tool is named after the buzz term “LSI keywords” contributes largely to it’s popularity in the SEO world.

The results returned by the LSIGraph are LSI or related keywords. You can upload these keywords in the free bulk keyword volume checkers like KeywordsEverwhere to get an idea.

The concept of TF-IDF in LSI keywords

While researching LSI keywords, knowing what of these keywords will make a difference to your rankings is a challenging task.

That’s where you need to do the is use the TF-IDF concept.

What is TF-IDF?

TF-IDF (term frequency-inverse document frequency) is a metric used by search engines to assess content relevance. It helps identify related keywords that frequently appear alongside the main keyword in multiple documents on the same topic.

Search engines use this information to determine how often LSI keywords should appear in a document to be considered relevant and authoritative on a specific subject.

There are free tools like Website Auditor from  SEO Powersuite, that can help you do the TF-IDF analysis of top ranking websites. By doing this, you can know what LSI keywords your SERP competitors are using and how often.

If it works for them, why not you?

The tool analyzes content from the top 10 search results for “LSI keywords”, generating a list of prominent multi-word and single-word keywords. It calculates the TF-IDF (term frequency-inverse document frequency) score, which indicates how often these terms appear in the documents. The tool also shows your page’s TF-IDF score for comparison.

Aim to match the average TF-IDF score of top-ranking pages. If you notice competitors using keywords that you’re not, consider updating your content to include these concepts.

Instead of focusing on an ideal keyword density, which varies by topic, look at what high-ranking competitors are doing. Rather than keyword stuffing, emulate successful strategies.

To save time and effort, research LSI keywords before writing. Create a solid outline that includes your main keyword and relevant LSI keywords based on competitor analysis. This approach is more efficient than adding keywords after publication.

How to use LSI keywords for SEO?

Let’s consider an example. Suppose you’re writing an article about healthy eating habits. Your main keyword might be “Mediterranean diet benefits”.

LSI keywords could include “heart-healthy eating”, “olive oil consumption”, “Mediterranean lifestyle”, etc.

When writing your post, include related terms like antioxidants, omega-3 fatty acids, whole grains, and longevity. These act as content relevancy signals.

However, if you start using terms like “ancient Roman cuisine” or “Mediterranean cruise”, Google might misinterpret your content’s focus. Stick to relevant terms and avoid keyword repetition.

You can see, the blog post effectively uses LSI keywords to target “Blogging tips for beginners”, incorporating terms like new bloggers, newbies, and beginners.

Here are key places to include LSI keywords:

• First and last paragraphs (alongside or replacing the main keyword)
• Throughout the blog post
• ALT tags (to avoid keyword stuffing)
• Social media titles
• Anchor text
• Text around internal links or backlinks

Remember to maintain appropriate keyword density. Google now prioritizes contextually relevant content over keyword repetition. As BloggingX states:

“Using LSI keywords in SEO-friendly and natural manner is better than using the same keyword often in your blog post”.

Use related keywords to signal content relevancy, not for stuffing. This approach makes your content appear natural and well-optimized.

When outsourcing blog content, provide writers with LSI keywords, a clear outline, and usage guidelines. Proper keyword implementation can significantly boost your SEO traffic.

Hummingbird and LSI keywords

In 2013, Google introduced the Hummingbird update, also known as the “Semantic Update”. This algorithmic change aimed to better understand user search intent using semantic intelligence.

Hummingbird interprets the context and meaning of entire queries, rather than individual words. This improvement enhanced Google’s voice search capabilities and results for new search queries.

With Hummingbird, Google began expecting certain keywords in webpages to ensure relevance to search queries. Previously, Google primarily matched entered keywords, which led to keyword stuffing abuse.

Post-update, Google prioritizes understanding keyword intent over exact matching. This update affected 90% of search queries.

Consequently, some authority sites without exact keywords but high relevance started ranking higher, while keyword stuffers lost rankings.

Hummingbird shifted focus from keyword optimization to topical optimization – optimizing content for narrow topics rather than specific keywords.

To adapt, use LSI keywords and address all relevant questions in your content.

Applications of LSI Keywords

LSI keywords typically have lower competition compared to main keywords. They offer versatile applications in various aspects of SEO and digital marketing:

Reviving dead content

Use Google Search Console to identify underperforming posts. Sort posts by descending order of impressions to find content that needs improvement.

Then, incorporate relevant LSI keywords to boost rankings and relevance.

Enhancing PPC effectiveness

Target LSI keywords in PPC campaigns to lower costs and increase ad visibility. This strategy works across various ad networks, including Google Ads, Bing Ads, and Amazon ads.

Sometimes, the combined traffic from LSI keywords can surpass that of the main keyword at a lower CPC.

This approach can help you reach a wider audience while optimizing your ad spend.

Image optimization

Instead of stuffing main keywords in image alt tags, use relevant LSI keywords. This approach can improve rankings and avoid potential penalties.

Ensure alt text remains highly relevant to the image. For example, if your main keyword is “healthy eating”, use LSI keywords like “nutritious meals” or “balanced diet” in your image alt tags where appropriate.

Backlink Campaigns

Diversify anchor texts in backlinks using LSI keywords to reduce the risk of penalties and create a more natural link profile.

For example, if targeting “furnished apartments in Seattle”, use variations like:

• furnished housing in seattle
• serviced apartments seattle
• furnished flats in seattle

Keep keyword-rich anchor text below 30-40% of your backlink profile, depending on the quality of linking sites and your niche. This strategy helps create a more diverse and natural-looking backlink profile, which is favored by search engines.

Wrapping up

Embracing LSI keywords is no longer optional in modern SEO—it’s essential.

By incorporating these semantically related terms, you’re not just optimizing for search engines; you’re creating richer, more comprehensive content that truly serves your audience.

Remember, the goal is to cover topics thoroughly, not to stuff keywords. As search engines continue to evolve, your focus should be on crafting high-quality, relevant content that naturally incorporates LSI keywords.

This approach will not only improve your rankings but also enhance user experience, setting you up for long-term SEO success.

And, finally!

Here’s an infographic for you to refer to!