## 3.2.1 Boolean operators

Boolean operators (AND, OR, NOT)

AND

- AND means that all words must appear in the search result
- You use the AND relationship to link two (or more) different subjects.
- The search result is limited, smaller than the one-word search.
- For example: you are looking for information about the relationship between obesity and nutrition in canteens. Search terms and relation: obesity AND canteens

OR

- OR means that at least one of the words appears in the search result
- the OR relation is used for (almost) synonyms, plural/singular, different spellings
- The search result is increased, extended compared to the one-word search
- Example: in addition to canteens, you also want to search school canteens. Search terms and relationship: canteens OR school canteens

NOT

- You can use the NOT relationship to exclude a certain word/subject
- The search result is narrowed down
- Example: you want information about canteens in schools, but not about canteens in primary schools. Search terms and relationship: schools NOT primary schools

Tips!

- Type AND/OR/NOT with capital letters
- Sometimes you can also use Boolean operators in Dutch, then it is: EN/OF/NIET
- If you combine several Boolean operators, put the OR terms between brackets. Example: (canteens OR school canteens) AND obesity. If you do not use brackets here, the AND command only works for school canteens AND obesity
- If you put your search terms in parentheses or quotes, these terms get high priority in the search.