|Author:||W. Brian Dill|
There are several Boolean expressions, but the most frequently used, and perhaps most frequently misunderstood, are OR and AND. These expressions are used to indicate a relationship between the words that you are using to search. In the physical world if you ask for bacon AND eggs you receive a larger amount of food than if you order bacon OR eggs. Thus "AND" implies a greater quantity than "OR."
In Boolean logic the opposite is true. In Boolean logic the use of "OR" returns a larger result set. If I searched for "tennessee AND titans," then I would most likely see only web pages that dealt with the Tennessee Titans NFL football team. On the other hand if I searched for "tennessee OR titans," I would still see the same links to the previous pages, but I would also see a myriad of web pages about anything and everything about the state of Tennessee as well as pages that dealt with mythological creatures. Assuming I want to find pages about the NFL football team, the use of "OR" will more precisely define what I am looking for and as a result, will have fewer but more accurate results.
To give you some metrics I searched for "tennessee titans" on www.altavista.com. When I used "OR" I received 4,361,155 matching pages. When I used "AND" that number was reduced to 1,534,775.
I don't know about you, but I don't have time to search through even 1.5 million web pages to find what I need. So how do I get better results? Our good friend double quotes come to the rescue. If two or more words go together to create a structured phrase, then you can enclose them in double quotes to achieve better results. Returning to our example, let's look at Tennessee Titans again. Since those two words go together as a phrase, it would be appropriate to enclose them in quotes. When I searched for "tennessee titans" on altavista I got only 6,942 pages. Now we are down to a reasonable number. I would expect there to actually be 6,000+ web sites that talk about the Tennessee Titans. To get a smaller result set we need to specify more keywords with which to search. For example, if I am looking to buy a cap or jersey I should search for "tennessee titans merchandise." When I do so I get only 10 pages as a result. Now we are down to such a small number that I can take the time to look at each one individually.
Use lowercase only unless you are specifically searching for upper case or proper case. Some of the search engines search differently based on the case of the keywords. For example if you search for "MASS" you will only get results with "MASS," but if you search for "mass" you will get results with "mass," "Mass" and "MASS." Some search engines do not pay attention to case so if you are unsure either look at their help page or use lower case to generate a larger result set.
The information in this article is of a general nature and the logic behind it can be applied to any search engine, but be aware that every search engine might have its own little quirks about how it implements these concepts. To find out exactly how a particular search engine works, take a minute to look their help page. It is usually labeled with "Help," "Search Help" or "Advanced Search."
There are literally hundreds of different search engines on the internet. So which one is the best? The best search engine is the one that gives you the most desired results. To determine which one meets that criteria, you will just have to try out some different search engines to see the results of your efforts. To get you started I have listed a small number of some of the more famous search engines.
Needless to say I am omitting a huge number of available search engines, but I can almost guarantee you that if you apply the techniques that you learned here, then you will find what you are looking for in one or more of the above search engines.
I have only taken a brief look at the logic of how search engines work, but I hope that you have learned enough concepts to enable you to have more accurate searches. With some practice and a little bit of research you will be well on your way to becoming a "search master." Happy searching!
|Brian Dill is a senior programmer at RealTracs, a MLS in Nashville. He holds certifications from Microsoft and Adobe and has experience in designing websites, graphics and web based applications. You can find out more about him at his website: www.leftandwrite.com/brian.|