Title: Section 1.3: Search terms and search strings
Course: MSc level academic and professional (information) skills > Section: Part 1. Information skills, Plagiarism and Referencing

Introduction to search terms and search string

Learning objectives

In this section you learn to determine the key concepts of a research question and how to find relevant search terms for your key concepts. With boolean operators you will connect the search terms into a search string.

After this section you will be able to:

- Determine the key concepts of your research question.
- Find relevant search terms.
- Make a good search string to enter into a database.

Keyconcepts of a research question

Great! You defined a good research question. But before you can search for literature to answer your research question, you need to determine what the main ideas of your research question are.

Databases do not work with natural language. That is why we need to enter a good search string to get relevant results. Search strings consist of search terms and boolean operators to connect them.

Determining the keyconcept

In every question there are parts that are the key to the whole question. Those keyconcepts are needed to define your search string.

Let's take a look at the following research question: Does handling pets influence crisis resilience in humans?

The keyconcepts in this question are 'pets' and 'crisis resilience'.

Words like 'influence', 'effect' or 'correlation' that are in your research question are not necessary in your search string. By putting together the words in a search string, you already imply there is a relation between the concepts.

Keyconcepts and databases

When you are defining your keyconcepts it's also important to think about the databases that you want to use for your research.

Take a look at the following research question: Do teaching skills influence grades for chemistry lessons?

When you use a chemistry database it is not necessary to use searchterms for chemistry, because the database only hold articles that deal with chemistry subjects.

Boolean operators

Once you've defined the keyconcepts of your research question, you have to connect those terms in a sensible way. Searching for one thing AND another, is a different thing than searching for one thing OR the other.

Boolean operators define the relationship between different terms. By using boolean operators to connect your term you are making a search string. There are three basic boolean operators: AND, OR and NOT.

How do boolean operators work?

Watch the short video below to see how boolean operators work.

What you are searching for by using boolean operators is highlighted in blue in the figure below.

Truncation and phrase searching

You now know how to use boolean operators in your search string, but there are other search techniques that make your searching more efficient. You can use for example truncation, wildcards or phrase searching.

Truncation and wildcards

When you want to search for different forms of a word, you can use truncation. When you truncate, you substitute one or more letters for a symbol. The symbol that is used most frequently in databases is the asterisk (*).

For example: help* gives you results with the word help, but also helping and helpful.

With truncation, you can search for singular and plural forms of a word, but be careful where you place the asterisk! It can give you unexpected results.

For example: car* gives you results on car and cars, but also carrots and cardiac.

Wildcards can be used when you do not know the exact spelling of a word,  with for example English or American spelling. With wildcards, you also substitute one or more letters for a symbol. Which symbol is used, depends on the database and can often be found on the 'help' page of the database. Often used symbols are (#), (?) or (*).

Phrase searching

When you want to find a group of words in a specific order, you can use phrase searching. Phrase searching is done by putting the phrase between dubble quotation marks "...." .

If you want to search for social media, for example. You do not wat to find results on the words social or/and media, you want results on the concept of social media. In a database you enter "social media" , to get results on the whole phrase.

Making a good search string

You defined the key concepts in your research question and looked at the different search techniques. But before we can put everything together, we need more search terms for our search string. To do this in a systematic way, we can use a table.

A table for search terms

The key concepts from your research questions are not always defined in the same way. Different articles use different terms for the same idea. You now need collect those different terms. This can be done by using a dictionary, encyclopedia, relevant research article, book or any other source about your subject.

Try to find synonyms for your key concepts, but also look at broader (more general) terms and narrower (more specific) terms. To get a good overview of your search terms you can use a table like the one below.

Remember the previous research question? Does handling pets influence crisis resilience in humans? Keywords for this question are 'pets' and 'crisis resillience'.

Key concept | Broader term | Narrower term | Related term / Synonyms
Pets | animals | dog, cat, rabbit | ...
Crisis resilience | crisis |  | crisis management
... | ... | ... | ...

Putting everything together

Now let's put everything together in a good search string using Boolean operators and other search techniques.

The table above is very usefull for combine search terms with Boolean operators. The general it can be said that terms that are placed horizontal are combined with OR. Terms that are placed vertical are combined with AND.

To keep your search string orderly, use brackets in your search string to group parts that go together. Let have a look at the search string for the research question about pets and crisis resillience.

1. Putting the search terms with Boolean operators:

pets OR animals OR dog OR cat OR rabbit AND crisis resillience OR crisis OR crisis management

2. Now use bracket to group parts that are connected with OR:

(pets OR animals OR dog OR cat OR rabbit) AND (crisis resillience OR crisis OR crisis management)

3. Use phrase searching and truncation where necessary:

(pet* OR animal* OR dog* OR cat* OR rabbit*) AND ("crisis resillience" OR crisis OR "crisis management")

Now your search string is ready to be entered in a scientific database!

Note: Remember, searching is a cycle. Once you've gathered results from a database, you can adjust your search string to get better results.

Exercise: Click here

The end of section Search terms and search string

Here ends the section Search terms and search string.

In this section you learned how to determine the different aspects of your research question and how to find good search terms for those aspects. With Boolean operators you can connect the search terms to make an efficient search string.

Defining search terms and making a search string are steps 3 and 4 in the cycle of systematic searching. Your next step will be to put your search string in a database and gather results. Go to one of the other sections to go deeper into the other steps in the search cycle.