1. Onderzoeksvraag2. Zoektermen – 3. Informatiebronnen – 4. Zoeken – 5. Selecteren van informatie – 6. Verwerken van bronnen

Simple or advanced searching
Searching techniques
Searching methods
Improve search results
Finding full text

Relations between search terms

We take the research question from step 2 ‘Finding terms’ as the starting point here:

‘What influence does the consumption of coffee have on the study success of students?’

If you are going to search with several terms at the same time, you have to indicate exactly what the relationship between the search terms is. There are three basic relationships between search terms:

  • Both terms must appear in the search result (AND), e.g. coffee AND students
  • At least one of the terms must occur (OR), e.g. students OR students.
  • This is also useful for synonyms, e.g. influence OR effect
  • A term must be excluded (NOT), e.g. coffee NOT energy drink. In Google, it is better to use the minus sign: coffee -energy drink

Graphically, the relations between search terms are shown as follows:

We call these tools for smarter and more targeted searching Boolean operators. AND, OR and NOT are the most well-known and used operators.

In many databases and search engines you will find a search form in the advanced search in which you can choose one of these options. Often you can also combine the different options.

Now that you know this, you can supplement the list of search terms created in step 2 with Boolean operators:

You can try out different search strings. You will see that different combinations give different results. For example, a search with may not give the desired results.

Compare this search string for example:

(influence OR effect) AND (coffee OR caffeine) AND (study success OR ability to concentrate) AND (student OR students)

With this search string:

(influence OR effect OR influence) AND (coffee OR caffeine) AND (study success OR studying OR concentration) AND (student OR students)

Copy and paste both search strings into a number of search engines (e.g. Google or DuckDuckGo) and compare the results.

How objective would the sources found be? For what purpose do you think the information was put online?

What do you notice when you apply the same search strings via Google Scholar?

Moreover, the use of round brackets is called nesting. See further: Nice to know: Termen nesten.

Other alternative should be given. Does not work, both search strings are the same.