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Psychology: DClin systematic literature searching: 4. Creating an effective search

This tutorial will guide you through the steps required to systematically search for literature for your service-related project and thesis.

Search words picture

You can test a search by checking whether known articles are appearing in the results list. If they aren't, this is a clue that you may need to revise your search and possibly add additional terms. Review these known articles for words in the title and abstract, author's keywords and, controlled vocabulary terms (if available). 

Can a librarian devise / review my search strategy for me?

No - this is not permitted. 

Devising a search strategy is a fundamental element of your assessed programme.

The Library does offer support on:

  • where to search,
  • using databases,
  • search techniques, and
  • saving and exporting search results.
After breaking your research question into discrete concepts, expanding those concepts to identify additional keywords, you will need to use the boolean operators (AND, OR, NOT) to combine the concepts into a search strategy for use in the databases. A good systematic search should be exhaustive, trading off specificity (how 'on topic' all of your results are) in favour of sensitivity (finding as much material on topic as possible regardless of how much other irrelevant material is captured). Both approaches have advantages and disadvantages it's about finding the balance for your topic!

Combining your search terms

It is possible to use a number of different keywords or search terms in a single search, by using operators. 

Operators link your search terms and define the relationship between them.

This enables more accurate searching and therefore more relevant results being returned. It also saves you time as you don't have to carry out numerous similar searches where just one or two search terms are changed each time.

The three most commonly used operators are ANDORNOT.  These are known as Boolean operators. They can be used to broaden or narrow a search and to exclude unwanted search terms and concepts.

Use AND to narrow your search.

Using AND between your search terms narrows your search as it  instructs the database that all your search terms must appear (in any order).

For example: CBT AND depression
                      - 
will only return results where both words are present

Because all search terms must be present, using AND makes the search more focused. 

In some (but not all) databases and search engines the AND is implied so if you enter multiple words the database will search for results which contain all/both words.

Use OR to broaden your search.

Using OR between search terms broadens your results as any or all of your search terms can be present.

For example: adolescent OR teenager
                      - will return results where either one or both of these words are present

It is extremely useful for finding synonyms or related concepts.

Using OR  enables you to carry out a number of similar searches in one go, saving you time.

Use NOT to narrow your search.

Using NOT narrows your search as it instructs the database to ignore results that contain particular words.

For example: social media NOT twitter
                      
- will return results that include social media but do not  include twitter

NOT  tends to be used less than the And and OR operators. 

Use it with care as you may exclude useful articles which cover a range of topics of relevance to you.

Databases usually process the Boolean operators in a logical order. They typically recognise AND as the primary operator and will connect concepts with AND together first.

When using a combination of AND and OR operators in one search, use parentheses (brackets) to group the OR words together so that your search is processed correctly. Alternatively, use the Advanced Search option to separate out your search terms (entering each concepts keywords in a separate search box), this saves you having to add the parentheses.  

Using search techniques to improve your search

Truncation 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 at the end.

The database will return results that include any ending of that root word.

The asterisk * symbol is most commonly used for truncation. However, check out the help screens as  !, ?, or # may also be used.

For example:

child* will find child, childrenchildlikechildhood etc.

Use it with care to avoid finding too many alternatives.

Wildcards are similar to truncation but they are used to substitute for a single letter or no letter in a word.

They are useful for irregular plurals and for British/American English spellings.

They broaden your search by including variant word spellings.

The question mark symbol is most commonly used. However, check out the help screens as  ! , *, or # may also be used. 

For example:

wom?n will find woman and women

optimi?ation will find optimisation and optimization

model?ing will find modeling and modelling

Phrase searching is the most limiting technique as it is used to specify that your terms must appear next to each other, and in the order you specify.

Phrase searching is commonly achieved by surrounding your phrase with quotation marks.

Always check the Database Help screens, as some databases may use different symbols.

Phrase searching examples:

"Cognitive Behavioral Therapy"

Proximity searching can help to both increase or narrow your results. It can increase your results when "phrase searching" is too restrictive.

Using an operator such as ADJ or NEAR  to define the proximity between your keywords can be helpful in increasing the precision of your results compared with using AND to combine the keywords 

e.g. mindfulness ADJ3 treatment returns results with the keywords "mindfulness" and "treatment" within three words of each other in either direction. 

Tip - check the help section of the database you are using as these operators differ across different databases.

Proximity searching should be used with caution in systematic reviews to avoid losing relevant studies.

Records in databases are made up of fields containing pieces of bibliographic information which describe the item in details.

Fields differ between databases but common fields include:

  • author
  • title
  • journal title
  • abstract
  • publisher
  • date / year of publication
  • subject / descriptor

If you are overwhelmed by search results, then using field searching can make your search more focused as databases usually run a keyword search against the full database record leading to a wider search.

In Ovid databases (i.e. APA PsycInfo and Ovid Medline) you can run a title / abstract search in the advanced search option. This search mode will allow you to manually enter the search codes after entering your keyword:

e.g. diabetes.ti,ab.

This example would search for the term 'diabetes' within the title and abstract fields of the database only.

Note: You will need to add a full stop following your keywords and separate multiple field codes by using a comma. Once you have entered all of the field codes that you want to search, finish by adding a final full stop. 

How do I create a search string / search strategy?

search string or strategy is a combination of keywords, truncation symbols, and boolean operators you enter into the search box of a database.

For example: 

(pain* OR discomfort OR “chronic pain”) AND (mindful* OR MBCT) AND (depress* OR anxi*)

 

asterisk * symbol is used for truncation i.e. to find various word endings and spellings for pain, mindfulness, depression and anxiety. 

quotation marks " " are used to phrase search the term chronic pain i.e. to specify that the terms must appear next to each other, and in the order you specify to avoid finding instances of these two terms separately within an article. 

 

OR is used to find the alternative words used to describe a concept or idea, for example, the different terms you may use to describe pain. 

Brackets are used to group the OR words together so they are processed together (if you are using the multi-field search option the database automatically enters the brackets around each search box). 

AND is used to link the search concepts together and find material that contains all aspects of your question.

If you are entering your search in one search box it is important that you use AND, OR and Brackets in combination so that the search is processed correctly. 

Alternatively, use the Advanced Search or Multi-Field Search options to separate out your search terms (entering each concepts keywords in a separate search box), this saves you having to add the parentheses.  

Recording your searching

Laptop with notesRemember you will need to describe your search strategy in your write up. It is easier to record this information as you go, than to try and remember it later!

You will need to include:

  • the keywords and search strategy used,
  • the databases searched,
  • search limitations applied,
  • the total number of results,
  • and screening procedures used.

It can also be helpful to note down the date of your searches for your own records.

  • Create a document listing all your keywords, relevant subject headings and search strategy (copy and paste from the database or take a screenshot).
  • Save your search strategy from each database – use the workspace in each database to save your final search. You can then print or export the information, as well as revisit it at a later date.
  • Create a simple spreadsheet to record the databases you have searched. Make a note of the date, the database searched, which interface you used (e.g. Ovid or EBSCO), the number of hits and the number of relevant results found.
There is no right or wrong way of recording this information, so come up with a system that works for you. The most important thing is you have the information you need for your write up!

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