Network analysis based on keywords
The following example explains how to create a keyword-analysis with VOSviewer based on a publication set. For that purpose the publications of the Nobel Prize winner in Physics in 2020, Prof. Reinhard Genzel, will be used. The following steps need to be performed:
1. Author search in Scopus
The publications, which contain the relevant keyword information, need to be extracted from Scopus first. In this case this can be realized by performing an authors search. The search for authors offers only one hit for "Reinhard Genzel". If there are several researchers found, the right one can be identified by the indicated affiliation.
A more detailed explanation of how to perform an authors search can be found here: Search for authors and the related author profiles
2. Create data basis
The function "Export All" can be used within the accessed author profile to export the shown set of data.
By using the function, a menu opens where the preferred method and information of export can be selected. For the usage within VOSviewer, the CSV-format (Excel) is recommendable. To do a keyword-analysis, it is also indispensable to select this information before exporting the data basis.
The CSV-file can now be exported by using the button "Export".
3. Visualize data in VOSviewer
The generated file can now be fed into VOSviewer. After starting VOSviewer, the keyword-network can be generated by using "Create". The function "Create a map based on bibliographic data" provides the opportunity to generate a keyword-analysis. In this case, the selected "data source" is "Scopus". Afterwards, the created data basis needs to be selected and and inserted into VOSviewer. In the next window, the "type of analysis" should be "co-occurrence" to have the opportunity to choose "All keywords" as "unit of analysis".
After that, a lot of different settings can be selected. First can be chosen, from which number of occurrence a keyword should be displayed. In this example five occurrences are obligatory for a keyword to be shown and 196 of the 1580 keywords of Dr. Genzel meet this threshold.
"Next" shows the following setting page, where the keywords can be verified and further reduced. Also with "Next" you get to a final view of the keywords, where you can adjust your selection again.
"Finish" ends the selection and generates a keyword analysis out of the authors publications on the basis of the selected parameters. The bars at the right side of the screen can now be used to modify the created network in terms of color or scaling. The generated network will look like this:
The bigger the knot, the more popular the related keyword. The lines between the knots show the connection between the keywords and illustrate how often they are used in combination. The colors refer to clusters, which visualize different generated topics due to the relatedness of the keywords among each other.
By moving the cursor over one of the knots, this one and the directly connected keywords will be optically highlighted, whereas the rest of the map will be greyed out to provide a better overview.
The exact numbers, that define the network, can be seen on the lower left side of the screen.