- Kevin likes a lot of different toppings. He prefers pepperoni AND sausage AND green peppers AND mushrooms AND extra cheese.
- Chris likes his pizza almost totally plain. He doesn't like meat that much. The pizza should NOT have pepperoni. He does NOT like sausage either. Vegetables are okay, but he does NOT like extra cheese.
- Sam isn't too picky. She wants pepperoni OR sausage. Green peppers OR mushrooms are good with her.
Eventually, they decided on a pizza with green peppers AND mushrooms, but NOT with pepperoni OR sausage.
Believe it or not, this pizza ordering example also describes the type of thinking you need to do when coming up with a good search. Search engines use special commands called operators. These operators use a special language called Boolean logic. They help you tell the computer exactly what words you want or do not want to include in your search.
There are three basic boolean concepts you need to know to work with in a search engine: AND, OR and NOT.
As you think about your search, formulating search phrases and predicting your ideal search results, you should think about words that you think should show up on your web web page. But keep in mind that people sometimes use different words to say the same thing, so you need to think of synonyms to use in your search. And sometimes there are words that get in the way of your search too.
You can't explain which words to include or exclude to a search engine. It's just a dumb computer. But you can use the search engine operators to perform this task. Because the operators are a special language, we have to capitalize all the letters of the operator so the search engine can distinguish them from their normal use.
Let's say I want to look up information about penguins.I want to find inforamtion for a science report. So I want to include information on habitat, diet and other relevant information. So, I want the web page to include the words habitat AND diet.
An initial search for penguins also includes information on the Pittsburgh Penguins hockey team. I do NOT want results that include the team. Also, the scientific classification name for penguins is Spheniscidae so I will include it. But I also want to include the common name penguines so that my search is broad enough to include pages that use the common OR scientific name. I wouldn't want to miss anything.
If I string all of that together, my search would look like this:
penguin OR Spheniscidae AND habitat AND diet NOT "pittsburgh penguins"
Search engines have their own way of expressing these operators. Google assumes that any words you put in the search box should be included in the page, so you don't have to put AND in the phrase, but you do have to use the OR operator. Instead of NOT, Google uses the minus sign (-) to indicate you want to exclude a word or phrase from your search.
So the same search in Google might look like this:
habitat diet penguin OR Spheniscidae -"pittsburgh penguins"
If you use the advanced search menu of most search engines, you don't even have to type in the operators. They usually have fields that do the same thing along with many other fields for tweaking your search.
Google's Advanced Search Screen
If you find that your search is returning no results, too few or the wrong information, strategically start to remove search terms and operators or use different ones until you get you want.