Boolean logic: the use of AND, OR and NOT to combine search terms

1
Boolean logic the use of AND, OR and NOT to
combine search terms

• Mary Last, UCLH NHS Foundation Trust
• Thursday 6th September 2007

2
Learning outcomes

• By the end of this session you will be able to
• Use the Boolean operators AND, OR and NOT to
  combine search terms
• Apply these in a range of search environments

3
AND

• Please may I have a gin and tonic?
• Ice and lemon?
• Yes please!
• You will have glass containing
• gin AND tonic AND ice AND lemon
• AND - All components are together

4
OR

• Tea or coffee?
• In everyday English youre being offered one or
  the other
• In databases youll get either or both
• Tea alone
• Coffee alone
• Tea and coffee

5
NOT

• Heres your tea. Milk and sugar?
• Just milk please.
• You will have a mug containing
• tea AND milk NOT sugar
• NOT - excludes things

6
AND
7
OR
8
NOT
9
Search tips large databases

• Build your search up one term at a time
• Combine search terms together
• use search line numbers

10
Search tips smaller databases

• Assumed AND is common on the Internet and in
  smaller databases, e.g.
• Intute www.intute.ac.uk
• TRIP database www.tripdatabase.com
• National Library for Health www.library.nhs.uk/
• OR needs to be specified
• Always read any available search tips

11
Examples

• A search for diabetes in pregnancyType diabetes
  pregnancy
• A search for items about talking therapies
  Type counselling OR psychotherapy

12
Simple v advanced search

• Simple search
• a single search box
• Advanced search
• two or more linked search boxes

13
Building up a complex search

• When there is only one search box
• When you need to use a combination of ANDs and
  ORs
• Enclose your ORed terms in brackets
• Prozac AND (anxiety OR depression)
• (teenagers OR adolescents) AND (anxiety OR
  depression)