Final Projects & Dissertations: Search Techniques

Boolean operators connect your search words together to either narrow or broaden your set of results. You can combine multiple Boolean operators to create more effective searches.

Boolean operators form the basis of database logic. You do not need to use them on sites such as Google (and Locate does not require them in the basic search screen), but they will make searching academic databases full of journals much more efficient.

The three basic Boolean operators are: AND, OR, and NOT.

AND

Use AND in a search to:

• narrow your results
• tell the database that ALL search terms must be present in the resulting records
• example: diet AND obesity: your results will include both words

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OR

Use OR in a search to:

• connect two or more similar concepts (synonyms)
• broaden your results, telling the database that ANY of your search terms can be present in the resulting records
• example: diet OR nutrition

NOT

Use NOT in a search to:

• exclude words from your search
• narrow your search, telling the database to ignore concepts that may be implied by your search terms
• example:  obesity NOT child

Some databases assume that words typed next to each other should be searched as phrases. However, many databases do not do this. Most academic databases automatically put a Boolean AND between your search terms; this means that all the words you enter into the search will be present in your search results, but not necessarily together.

For example if you search for living standards, you will get results for everything that has the individual words 'living', and 'standards' but not necessarily the most relevant results where the two words appear together as a phrase. When this happens, your search results may not be useful for your research focus, and you will probably have too many results to realistically look through. 

To avoid this happening, you can use "double quotation marks" to keep words together when you search. This way you will only get results where these words appear together as a phrase. 

For example:

    "later life"

    "maternity leave"

    "living standards" OR "standards of living"

In order to get the best and most relevant search results you need to pick out the key concepts from your research topic or question. These are the main ideas that you will be researching. 

Here is an example of a topic, if we search for this as it is we won't get the best results for a few reasons:

Do business organisations have moral responsibilities?

The first reason being there are some words that won't work effectively when talking to a computer (searching a database) and the second being there are lots of other words which authors use to describe the topics contained in this question.

The first thing we want to do is take out the words that make the sentence readable but don't mean anything without context (a computer has no context to interpret these words and they will just bring up lots of irrelevant results), this is usually any words like 'the' 'have' 'to' etc. We just want the words that represent the key ideas:

Do business organisations have moral responsibilities?

So, business organisations and moral responsibilities are the key concepts here. 

Keywords are words or short phrases that represent the main ideas (key concepts) in your research topic or question.

In search engines like Google, you can search using full sentences. However, some Library databases are not as smart as Google and do not understand full sentences, spelling mistakes or conversational language. This means that when you are searching, you need to break your topic into keywords instead - you have to consider the words that authors are using to write about a topic. 

For example:

If you are writing an assignment on the impact of diet on child obesity, your key concepts (main ideas) would be: diet, child, obesity, child obesity.

For each key concept, try to think of as many similar or related words as possible. This can include:

• synonyms (words with the same or similar meanings)
• broader/related terms (words that expand or widen your topic, more general than synonyms)
• narrower terms (niche or specialist terms to really hone in on a specific area or research)

When you search for sources using a range of different keywords, you will find more search results that are relevant to your topic.

Once you have found your keywords, you can combine them using the Boolean Operators AND, OR and NOT, as described in another box on this page.

Truncation (or 'wildcards') is a technique that broadens your search to include various word endings and spellings.

• To use truncation, enter the root of a word and put the truncation symbol (normally an asterisk) at the end.
• The database will return results that include the word that you entered, plus any ending.

For example:

nurs*        finds:  nurse, nurses, nursing

child*        finds:  child, children, childhood, childbirth

manag*    finds:  manage, manages, manager, management etc.

midwi*      finds:  midwife, midwives, midwifery

On some databases, you can also use a wildcard in the middle of a word to include both English and American spellings

    e.g. col*or, organi*ation

Tip! Be careful not to truncate too soon.

    e.g. leg* or comp* will retrieve too many false results