michigan informatics

Search Engines

Search engines are wonderful. They search enormous amounts of data quickly and often take you directly to the information that you need. However, search engines include everything- authoritative resources, homework assignments by nine year olds, advertisements disguised as health information, anything at all. There is almost no human involvement in the selection of the sites included and there is little or no organization of them.

Search engines contain vast amounts of information, which is useful if you’re looking for something very particular that has a unique name. However, if you are searching for general information or using common terms, they often give an overwhelmingly large number of results that are of little use to you.

You will greatly improve your ability to use a search engine by understanding exactly how search engines work.

How Search Engines Work

There are four distinct parts to a search engine which will affect your search results.

1. The web crawler. Each search engine has a “web crawler” or “spider” or “robot”, which is a computer program that scours the Web looking for documents.
2. The database. The documents that the web crawler finds are then added to a database and indexed by title, text word, links, and other content found on the page.
3. The search algorithm. The search algorithm translates what you type into the search box into a query of that database.
4. The ranking algorithm. The ranking algorithm will sort the results from your query into a list, hopefully with the most relevant documents at the top of the list.

These four parts of a search engine each have significant impact on your search. Each search engine uses a different web crawler, searches a different database, and translates your query with different algorithms. This is why it is good to use more than one search engine.