Mastering Boolean Logic for Effective Searching

1. Boolean Logic Combining search statements using Boolean operators

2. Boolean searching - OR In database searching OR expands a search by broadening the set. It is often used to combine synonyms or like concepts. Example 1. Use Boolean logic to describe an ice cream lover with global tastes (the coloured area) Strawberry OR chocolate OR vanilla Bolean Logic

3. Boolean searching - AND In database searching AND narrows a search. It is often used for linking together different concepts. Example 2. Use Boolean logic to describe an ice cream lover who only eats ice cream which combines 3 flavours at the same time e.g. Neopolitan ripple (the coloured area) Strawberry AND chocolate AND vanilla Bolean Logic

4. Boolean searching - NOT In database searching, NOT is used to get rid of an unwanted concept. Example 3. Use Boolean logic to describe an ice cream lover who won’t eat chocolate (the coloured area) (Strawberry OR vanilla) NOT chocolate But BEWARE! – you may also exclude relevant articles. Bolean Logic

5. Boolean searching - PARENTHESES Parentheses define the order in which the concepts are processed. • AND takes priority • OR is processed last SALMONELLA HAMBURGERS EGGS Use parentheses to ensure terms are processed as intended Bolean Logic

6. Some examples Example 4: Find information on the influence of eggs on salmonella food poisoning caused by hamburgers • salmonella AND hamburgers AND eggs = food poisoning caused by both together • (hamburgers OR eggs) AND salmonella = food poisoning caused by either • hamburgers OR eggs AND salmonella =Do you want eggs and gastro with your hamburger, or would you rather have fries? • (hamburgers AND salmonella) NOT eggs = = only food poisoning caused by hamburgers (removing the confounding effect of having eggs at the same time) Bolean Logic

7. Breast Cancer Smokers Women Ex-smokers A more complex example • Use Boolean logic to describe: • Women who have breast cancer but have never smoked • Women who have breast cancer and who are EX-smokers Bolean Logic

8. Breast Cancer Smokers Women Ex-smokers A more complex example Women who have breast cancer but have never smoked = (women AND breast cancer) NOT smokers Women Ex-smokers Bolean Logic

9. Breast Cancer Smokers Women Ex-smokers A more complex example Women who have breast cancer and who are EX-smokers = women AND breast cancer AND ex-smokers Bolean Logic

10. Breast Cancer Smokers Women Ex-smokers Another complex example Men who have breast cancer and who currently smoke = (men AND breast cancer AND smokers) NOT ex-smokers Bolean Logic

11. Reference Reference: Henderson J & Strickland J. Ithaca College Library Research Guide: Boolean Logic. Accessed at: http://www.ithacalibrary.com/sp/subjects/boolean on January 24, 2010 Bolean Logic