Website Tips

What is Latent Semantic Indexing and How Do SEO Professionals Use It?

latent semantic indexing

latent semantic indexingHave you ever wondered how keywords are generated to contribute to your SEO services?


Internet users want only to see the most relevant information possible. In fact, Internet searchers only read 28% of what they see on a web page, and that includes search results.


Latent semantic indexing, or LSI, sounds a lot more complicated than it really is. Basically, it’s the process that search engines use to find patterns within documents, and how they turn up the best web results. SEO firms use software to generate keywords based on how the patterns are registered.


In the English language, the most common words don’t really have meanings at all. They’re what we call functional words. They include conjunctions, prepositions, auxiliary verbs, pronouns, and more. They’re the words that help us form full sentences. But what’s between them — the content words — is what really matters.


In the first step of latent semantic indexing, the content words are extracted from the body text of the document they appear in.


From there, the content words and documents are used to generate the axis of a grid. This grid — the technical name is a term-document-matrix — displays how and where the content words appear.


Think of an ‘X’ in the content word column whenever that word appears in a document. When you do this for every word and document in the grid, the grid is mostly blank. This is what you know about your document collection.

The next step is a much more complicated process that is far more in-depth than what can be explained in this blog post. Singular value decomposition is a mathematical algorithm that allows these terms to be optimally used by search engines to generate the best possible results.


In the most basic terms, it’s kind of like word association.


In order for your website to show on the front page of search engine results, a combination of proper keywords has to be typed into the search bar. The words you type in are going to determine the most relevant results. Latent semantic indexing is the process that allows this to happen.


For example, when you type in “design,” you’ll likely find a culmination of results that vary from home improvement to architecture. But when you search “web design,” you’ll find a more relevant topic search. It’s the combination of content words in a specific order and grouping that help us generate the right keywords to use for your campaign.


At MRN Web Designs, our SEO professionals are able to get your campaign started by first developing the keywords that your site pages will be ranked on. To get started with a free consultation, contact us today!