Latent Semantic Indexing – An Intriguing Information Retrieval Technique

Recently Google has brought about a new indexing technique called Latent Semantic Indexing (LSI) for efficient information retrieval. Actually this concept was first used in Google’s Adsense program to find out the most relevant adverts on a particular site. Later a Google owned company named Applied Semantics took shape to help Google employ latent semantic indexing concepts and ideas in its search ranking procedure, and other search engines in the market immediately start using this concept for quality indexing purpose.

In non technical terms LSI is the human-like search ability of the search engines to find out most relevant information using the concept of semantically related words for a particular keyword search. Latent semantic indexing is nothing but the outcome of the search engine efforts in improving its search rankings and result display system further. In view of most of the web users falling prey to irrelevant websites from top search engine rankings, the search engine ranking procedure has lost its due importance. There is a strong urge among search engine makers to modify and update its old ranking system as its ranking algorithm was mainly based on number of links, votes and keywords and suffers from major setbacks resulting in penalization of pretty good sites for no fault of theirs in the mean time. Due to this many sites full of irrelevant keywords, inferior content and linking heavily to other irrelevant sites or even link farms can occupy top positions in search engines and webmasters as well as SEO professionals has started taking undue advantage of it. To stop this discrepancy from occurring further and bring transparency to search engine ranking, search engines revised their major criteria like keywords and links going in and out of the site and considered using synonymous word search facility to add quality and relevance to it. Thus LSI technique has started paying dividends in search engine arena recently.

LSI technique is not that much clumsy, and following it, one can easily build and organize his/her webpage to be found out by search engines successfully for a particular keyword search. Based upon the concept of semantically related words LSI algorithm scans your whole website content for searched keywords, and then establishes relationship between found key phrases and keywords. It even compares them with the already indexed websites for the same keyword and finds synonymous words and phrases. Latent semantic indexing also involves checking grammar, spelling, terminologies and the like on your website and other relevant sites which are already indexed. To be precise, the overall content of your website gets scanned and checked for particular search query text and ranked in the order of its relevancy as compared to already indexed relevant sites in latent semantic indexing mechanism.

A search for keyword “cellphone” on a search engine will bring sites having the highest occurrence of word “cellphone” or links pertaining to it whereas under LSI, a search for the same keyword will display sites that also have the word “mobile phone” or “cellular phone” or any other synonymous terms. Sites with quality and relevant content will always win over sites using illegal practices like keyword stuffing or link spam in higher search engine ranking race. Now, efforts of webmasters and search engine optimizers following ethical SEO practices have started paying results by bringing their site on top positions of major search engines and throwing away irrelevant and rubbish websites from the index list completely. Thus latent semantic indexing decides ranking and performance of a website from its quality and relevancy.