Tuesday, November 29, 2011

Search School: How a Search Engine Works

Welcome to Search School. Today, we begin a series of posts about searching electronic sources more effectively. If you asked around, you would probably find that most people (students and teachers alike) don't know how search engines work. Of course, most folks know how to put a few words in the search box and how to click on results. But they don't know how the search engines or LRC databases do their work behind the scences.

You don't have to be an expert, but having a general idea of how these programs come up with results can help you put together a better search, which leads to better answers. This video from Google gives a basic overview of how their search engine interprets your search and returns results. Although their approach varies slightly from other serach engines and library databases, the concepts are similiar enough.

Video Review

  1. A search engine creates an index of web pages that it finds on the web (like a book index). 
  2. The index makes note of the words on the page. 
  3. When you do a search, the search engine matches the words you type in the search box with information in its index.
  4. That means the pages in the search results contain your search words somewhere on the page and the more pages that have your keywords on them, the more results the search engine returns to you.

Next time, we will start a series of posts about how to formulate a better set of keywords.

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