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Boolean Search Techniques for the Web

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Presentation on theme: "Boolean Search Techniques for the Web"— Presentation transcript:

1 Boolean Search Techniques for the Web
OR How Do Smart GRRLz Search The Web?

2 Smart GRRLz . . . . . . search the web and databases by using Boolean logic. Boolean logic is named for George Boole, who was a famed English mathematician. Using Boolean logic makes your searches more effective and accurate. We’ve covered WHAT do Sweet Briar students search. Now we’ll look at HOW Sweet Briar students search.

3 Boolean logic offers three search options:
AND NOT OR I know they don’t sounds like much, but you have already used an “AND” search and you probably don’t know it! SBC Students search using Boolean logic.

4 AND is the most frequently used Boolean search
A search using AND will look like this: poverty crime You do not have to type the word “AND.” Just put two or more words together in a row. The computer assumes that the blank space between the two words equals “AND.”

5 This sequence tells the computer, “I want all the articles in this database that include both of these words somewhere in them.” The gray area on the right indicates the items that include both the word “poverty” and the word “crime.”

6 The AND operator works like a funnel-shaped filter
The more search terms you use (with spaces in between them) the fewer and fewer results will come back from your search. These fewer results will be specifically focused on your particular area of research.

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13 I’m going to demonstrate how this works in Google!
I’m going to show you how the Boolean operator AND works in Google! Google makes it easy for you to see what I’m talking about . . .

14 We will use the AND search
poverty crime Into Google

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16 This Boolean AND search brings back only articles that contain the word poverty and the word crime somewhere in them. As you can see, we got over 38 million results with this search! That is too many to look at. In order to focus this search and bring back fewer more specific results, we will add another search term to this string.

17 We’ll add the search term “nutrition” to this string.
Do you think the number circled in red will go up or down, now that we have three search terms?

18 If you guessed that the number would go down, you were right
If you guessed that the number would go down, you were right! We now have only four million or so results to choose from. What can we do to narrow this search further?

19 That’s right. We can add another search term
That’s right! We can add another search term. In this case we are adding the word Florida.

20 As you can see, we are down to 628,000 search results.
Let’s add one more search term. We’ll add the name of a small county in the north of Florida, Wakulla.

21 Now we are down to 288 search results, by using the Boolean AND operator!
Are there any questions about the AND operator?

22 NOT! The second most popular Boolean operator is NOT.
NOT works like AND in that the more search terms you use with NOT, the fewer and more focused your results will be.

23 If you did a search for articles about cats, but you did not want to get any articles about dogs in your search results, you would enter: Cats –dogs The grey area on the right represents the search results that include only cats, not dogs.

24 I demonstrate the NOT operator in eBay.
If you learn how to use it there, you can use it anywhere. In most search engines, the NOT operator is represented by a minus sign in front of the word you do not want in your search. For example: Clinton -Whitewater

25 Notice that in this eBay search we looked for “cell phone
Notice that in this eBay search we looked for “cell phone.” We got back 38,408 results. We can’t look at that many results, and some of these results are not for the phone itself, but for other things like “phone case,” “data cable,” battery, holder, parts and faceplates. How do we get rid of all those items that we do not want and find search results for a simple cell phone?

26 We perform a Boolean NOT search by placing a minus sign in front of each of the items we do not want to see in our search results. In this case, we told the computer “Please find a cell phone, but not a battery, not a faceplate, not parts, not a case and not an antenna.” Our results went down from about 38,000 down to around 23,000 items.

27 What if you wanted information about floods caused by rain?
You don’t want anything about New Orleans and you are not interested in hurricanes. What would your search string look like?

28 It might look like these . . .
Flood rain –hurricane –”new orleans” –levee Or Flood rain –levee –levees –floodwall –surge Flood rain –katrina –rita –overtopped

29 Notice that there is NO space . . .
. . . between the minus sign and the following word! Flood rain –hurricane –”new orleans” –levee Or Flood rain –levee –levees –floodwall –surge Flood rain –katrina –rita –overtopped If you left a space between the minus sign and the next word, what kind of search would that be? It would be an AND search. Are there any questions about the NOT operator?

30 OR The third and last Boolean operator is OR.
OR is less frequently used, because it does the opposite of what AND and NOT do. That is, it explodes your search results. It does not give you fewer. OR gives you MORE search results.

31 If you enter a search like this one . . .
college OR university OR campus Your search results will include every article with the word “college,” every article with the word “university,” and every article with the word “campus.” It doesn’t matter if they are all in the same article or not.

32 When to Use the OR Operator
The OR operator is used when the thing you are looking for has more than one legitimate name. For example: “Standards of Learning” is also called “SOL.”

33 The other time to use the OR search . . .
. . . is when you want to find every article on your subject, even if the name of the subject is spelled wrong in the article. In the next example we will search for three variations on Edgar Allan Poe’s name. Sometimes he was called E.A. Poe instead of Edgar Allan. And what if you did not know how he spelled “Allan?”

34 I’m searching here on E. A
I’m searching here on E.A. Poe, Edgar Allen (with an E) Poe and Edgar Allan (with an A) Poe. Notice that the O, R is capitalized in this search. If you do not capitalize the OR, the computer will think you are searching for the word “or,” instead of doing a Boolean OR search.

35 In this results screen, you can see that this Boolean OR search brought back over 9 million results. Now you understand why we don’t use the OR operator very often! Are there any questions about the Boolean OR operator?

36 “Phrase Searches” Some of you may have noticed that in the eBay search we did earlier I put quotation marks around the words “cell phone.” I did this so that the two words would stay together in my search results in that order.

37 If you search for: Cell phone Without quotes around the two words, what kind of search is that? That kind of search might bring back a page that says “James was on the phone when police arrested the members of a terrorist cell.” And that would not be what you wanted . . .

38 To prevent this kind of confusion . . .
. . . we place quotation marks around any two or more words that we want the computer to find in exact order. It even works with names. For example: “e.a. poe” “edgar allen poe” “edgar allan poe”

39 It’s good to use phrase searches when you are looking for the name of an . . .
. . . organization: “national rifle association” “win with women” “american association of retired persons”

40 You can even combine Phrase Searches with AND or NOT searches
. . . to get very specific results: “while I pondered weak” poem “sugar magnolia blossoms” lyrics “thank god almighty I’m free” speech

41 Do you . . . . . . Think you can do Boolean searches on your own now?


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