Truncation, wildcards, and phrases

Truncation

Truncation is sometimes referred to as stemming or root expansion. Words with different spellings often have the same ‘stem’ in common. For example:

• Organisation
• Organisations
• Organisational

These words all have organisatio.... in common. A specified symbol can take the place of the remainder of the word, enabling a search for a number of words using a single query.

The symbol may be:

• Organisatio*
• Organisatio?
• Organisatio$

Truncation symbols vary so check which symbol to use for each database. Take care not to shorten the word unnecessarily as this is likely to result in a very large number of unwanted results. For example organis* will return results with the terms organism, organised, organise etc.

Wildcards

A wildcard (or a universal character) is a symbol that is used in place of one character, no character, or a group of characters. Wildcards are usually used in the middle or end of words, not normally at the beginning. Databases vary in their rules for wildcard searching and in the symbols used, so always check the ‘Help’ section of the database you are using for more information.

Wildcards may be used when searching to retrieve all spellings of a word:

Plurals:

• Woman or women: Wom?n
• Trustee or Trustees: Trustee?

Alternative spellings:

• Behaviour or behavior: Behavio?r
• Paediatrics or paediatrics: P?ediatrics

Phrases

Sometimes you may wish to search for a phrase rather than a word, such as ambulance service. It is important to find out whether the database will automatically convert two words into a phrase search, or whether double inverted commas are required, such as “ambulance service”. The database ‘Help’ section will provide this information. You may also search the phrase as a keyword search (without MeSH terms applied).