Research Skills for Health: Search Strategies and using PICO

The next step of your search strategy is to apply Boolean operators (AND OR NOT) and field tags (where in a document you want to search for your terms, title, abstract, keywords, main headings etc.).

If you write your strategy out like this, it will be easy to add into your protocol and also you can then use copy and paste it into the database search boxes.

When doing systematic reviews, it is advisable to write out and search the controlled vocabulary terms separately as these can differ across databases and can affect your search results (see the free text vs controlled vocabulary box on the right).

Concept 1: Child

[Title / abstract]  

Children OR child* OR pediatric OR paediatric OR infant OR toddler OR preschool

[Controlled vocab: Main Heading / MeSH]

Child OR preschool

Concept 2: Preoperative

[Title / abstract]  

Preoperative OR perioperative OR peri-operative OR pre-surgery OR "preoperative period" OR "preoperative care"

[Controlled vocab: Main Heading / MeSH]

"Preoperative period" OR "preoperative care"

Concept 3

[Title / abstract]  

Music OR "music therapy" OR "music intervention" 

[Controlled vocab: Main Heading / MeSH]

Music OR "music therapy"

Concept 4

[Title / abstract]  

Anxiety OR distress OR "reduced anxiety" OR calm* OR relax* OR "anxiety reduction"

[Controlled vocab: Main Heading / MeSH]

Anxiety

Turning it into a search string

If you are doing a general search for information, you can just use the controlled vocabulary terms as part of your search string, so your search might look like:

(Children OR child* OR pediatric OR paediatric OR infant OR toddler OR preschool) AND (Preoperative OR perioperative OR peri-operative OR pre-surgery OR "preoperative period" OR "preoperative care")  AND (Music OR "music therapy" OR "music intervention")  AND (Anxiety OR distress OR "reduced anxiety" OR calm* OR relax* OR "anxiety reduction")

If you are doing a systematic search, you will need to separate them out as different databases use different thesauri/subject headings so you'll need to adapt the terms for each one.  A systematic search string might look like this. (Note:  In PubMed I've found that you need to put  [MeSH Terms] after each MeSH term rather than just using the drop down menu, otherwise it only searches one term as MeSH and the rest as All Fields - also, when you add the field tag in brackets afterwards, it is easier to copy and paste in rather than use the drop down menu each time.)

Database: PubMed.

Methley, A. M., Campbell, S., Chew-Graham, C., McNally, R., & Cheraghi-Sohi, S. (2014). PICO, PICOS, and SPIDER: A comparison study of specificity and sensitivity in three search tools for qualitative systematic reviews. BMC Health Services Research, 14(1), 579–596. https://doi.org/10.1186/s12913-            014-0579-0

AND - Narrows your search to find documents that have both 'this' term AND 'that' term.

OR - Expands your search to include a variety of similar terms e.g. teenager OR adolescent OR youth

NOT - narrows your search to remove documents that may be related to your search but not relevant to what your research is looking for e.g. surgery NOT veterinary 

Some databases require these terms to be in uppercase, so it good to get into the habit of always using upper case for these terms.  (You don't need to in OneSearch)

Truncation - use an asterisk (*) after a stem term to expand your search e.g. behav* should search for behaviour, behavior, behaviors, behavioral etc.

Phrase searching - put quotation marks around a group of words that you would like to search as one term.  It helps to narrow your search, e.g. instead of music therapy (which will search for music and therapy as separate terms) try "music therapy".

Brackets - it can be useful to group your search terms into brackets, particularly when using engines with only one search bar e.g. (child* OR preschooler or infant) AND (preoperative or surgery) AND (music OR "music therapy) AND (anxiety OR distress)

Why is it useful to search both free text and controlled vocabulary?

Controlled vocabulary (also known as subject headings or thesaurus) refers to the terms that have been attached to a document in a database.  Indexers read the documents and select the best terms from a predetermined list of words that best describes the topics of an article.  So for example if you are searching PubMed, which uses the Medical Subject Headings (MeSH), if an article has been written about heart attacks, it will always have the term myocardial infarction attached to it.

Using controlled vocabulary can ensure that you are using the best term that will find all articles associated with your topic.

However, it is still useful to also search free text keywords (such as "heart attack") as:

• Different databases used different controlled vocabulary.
  • When searching systematically it is useful to demonstrate these differences and helps you to adjust your 
• New articles may not have been indexed yet, so if you were to only use the MeSH terms, you may miss new research.
• There may not be a subject heading for the concept you are researching.
• Some newer words (e.g. augmented reality) may have only been added to the thesaurus recently and won't search articles on the topic that were indexed prior to this.