Getting Started

Is this an accurate description of 'total link strength'?
‘Total link strength’ measures the number and breadth of ‘links’ of one journal with other journals. For example, a journal with given number of co-citations could be frequently co-cited with either a smaller or larger number of other journals. This implies that a journal with higher total link strength has been co-cited with a larger number of other journals.
Thanks.

Dear Ludo,
I would like to know if there is a possibility to prevent nodes or labels from overlapping in the network view. Is it possible to make all labels apparent in VosViewer?
Thank you very much for your attention,
Lucas Carvalho

Just wondering if there's any way to increase the maximum virtual memory? I have been trying to create a map of 51,000 citations and it crashes out indicating that it run out of virtual memory. I've manually given Java 32 GB which should be plenty enough from what I can see within task manager of what It usually crashes out at around about 1 GB to 1.5. I'm assuming the restriction is within the software. The other option which I was wondering if possible was to merge smaller maps together.

hi. could you please explain to me how to use endnote data in the VOS viewer?

Dear Ludo,
First of all, I would like to thank you for the opportunity to ask questions through a direct channel. I am very interested in exploring Wikidata from VosViewer. However, I have been having difficulty finding the DOI of Wikidata articles. How should I proceed?
Thank you so much in advance.
All the best,
Lucas

Hi, please, anyone can help me, how to create a map with Endnote file? How can I prepare Endnote file? Is there any instructions with details? I have a small number of articles in an Endnote group to be analyzed. But the file type confused me. Thanks a looot!

I just wonder if VOSviewer can allow users to input additional numerical data in an extra column in the data file, e.g. Altmetric score, or score showing the location in a spectrum of basic science-applied research, etc. These data are not export-able or available in Web of Science or Scopus, but are informative.

I have a database consisting of 1,529 articles published in a single journal. When I ran journal co-citation analysis, it showed two journals with more than 1,529 citations. Is this due to those journals having multiple 'co-citations' in some of the documents?
Thanks.
Philip

Dear LudoI am working on constructing a co-occurrence network of keywords. During "Create map Wizard" I have chosen these options:1. Create a map based on bibliometric data2. Read data from bibliometric database files3. Type of analysis: co-occurrence; Unit of analysis: All keywords and Counting method: Full CountingI am trying to understand the difference between Full Counting and Fractional Counting methods in my case. I read on VOSviewer manual: Occurrences. When working with keywords, the Occurrences attributeindicates the number of documents in which a keyword occurs. When working withterms, the definition of the Occurrences attribute depends on the countingmethod that is chosen in the Create Map wizard. In the case of binary counting,the Occurrences attribute indicates the number of documents in which a termoccurs at least once. In the case of full counting, the Occurrences attributeindicates the total number of occurrences of a term in all documents. The difference between counting methods in case of co-occurrence network of terms is clearly explained. 
Furthermore I read: "Constructing bibliometric networks: A comparison betweenfull and fractional counting" by Antonio Perianes-Rodrigueza, Ludo Waltmanb, Nees Jan van Eckb. In this article there are given examples only for co-authorship, bibliographic coupling, and co-citation networks. Please can you help me understand the difference between full and fractional counting methods in co-occurrence networks of keywords?Note : I use VOSviewer version 1.6.13
Thank you in advance

Dear Ludo,
We are constructing a co-citation map with the most cited journals regarding a determined subject. When we construct this map, there are two different clusters with many journals. We are trying to understand how works the journals' classification into these two clusters. Is it based on the link strength among the journals? Citations among them?
Thank you in advance.

Dear Sir/Madam
I am trying to increase memory available to VOSViewer in the command line by using the cammand "java –Xmx4000m -jar VOSviewer.jar", but it says: "Error: Unable to access jarfile VOSviewer.jar". Could you please help me to solve the problem?
Thanks

Dear Sir/Madam,
I am trying to use the Vosviewer software for Bibliometric analysis, but each time I get a pop message that the excel file from scopus have some wrong quotes. What should I do?

Dear Ludo,
Thanks again for providing us this powerful tool.
I’m facing a problem with the bibliographic coupling analysis. When I try to model a network of bibliographic coupling generated by 6000 documents, VOSViewer pop ups an error message: “The number of clusters is too large. Choose a lower value for the resolution parameter”. I have already altered the resolution parameter to lower values (e.g. 0.1 or 0.001) but the same problem occurred. I also changed the minimum cluster size (e.g. 1000), without success.
When I model the network selecting only the giant component, this problem doesn’t appear. But for me is very important to generate a network including the unconnected items.
Thank you so much in advance.
All the best,
Antonio.

Hello,
Thank you for developing this very useful tool!
I'm conducting some analysis of data from Scopus (.csv format) and I'm getting the below error when loading multple files. Could you please advise on how can I resolve it?
Error while reading file 'scopus.csv': IOException reading next record: java.io.IOException: (line 198) invalid char between encapsulated token and delimiter.
Thanks for your answer
Diana

Dear Ludo,
Greeting for Australia. Thanks for developing this software and maintaining this page. I have a question about the termhood. I just wonder if the item relevance scores can be used as termhood value? or should I separately calculate the termhood score using, say, C-value?
thanks

Hello,
First of all, thank you for the program. While analyzing the most cited journals, I encountered the no title captured status. Is there anything I can do?

Hello,
I've only just started using this tool but I enjoy it already, thanks for the great work!
I'm trying to build a network using data from both WOS and SSRN. Is there any way to incorporate data from the SSRN database into the WOS format?
Thanks for your answer!
Sophie Korth

Hello
Seasons greetings for 2020.
I am facing a problem and hoping you have a solution for this.
1. VOSViewer produces totally different coauthor network with and without the "Reduce first names of authors to initials". Is this a bug?
2. The feature in (1) above is reducing names to single initial so introducing error in the network. For example, it takes Li, Y, Li, YL, Li, YH as one name - Li, Y.
Look forward to your help with this
Thx
Arun Saxena

Hello,
thank you for developing VOSviewer. I really enjoy using it. One question: Is it possible to show the names of all nodes in the screenshort? Can I somehow force the program to print all the names in the visualization?
If not, is it possible to tell the program which names to show in the screenshot? This would be very helpful.
Thank you and best regards!

Ludo:
I have an author co-citation map in the domain of problem-based learning that is comprised of 99 authors or a specific period of time (i.e., not the entire period of the review). In two of the three clusters, all of the scholars represented on the map are associated with 'medical education'. Of course, there were also scholars working on the design of PBL curricula in nursing, dental and engineering and management education as well. But they are not shown on the map since they did not meet the citation threshold.
I wish to name the schools of thought and am curious whether you think it is more accurate, for example, to call a school "Design of PBL Curriculum" or "Design of PBL Curriculum in Medical Education"?
Thanks.

I just started using VOSviewer and find it an amazing tool for bibligraphic network visualisation. But, when I make coauthorship network for the countries, the labels all begin with small letter. Can you please tell me how to make the Labels start with a capital letter.
Thanks.

I would like to use "corpus files" and "scores files" to create maps relating journal names and their impact factors. In “corpus files” I entered the names of the journals and in “scores files” I entered the respective impact factor. However,by generating the map, the full name of the journal does not appear, only the terms of the names. I tried to use “thesaurus file”, but I couldn't solve the problem either. Could you support me to be able to generate a map with the full name of the journals? The rest (legend according to impact factor) and circle size are correct.

Please give step by step procedure to draw network diagram of co-occurrence using Dimension database.
Thanks and Regards,

Please answer about my query. I am not getting the Web of science database.

I am fascinated with the VOSviewer. I am finishing a paper using it but would like to give access to the map or make the map available online. I have seen the publication on Analytical Chemistry: Bibliometric Mapping: Eight Decades of Analytical Chemistry, WithSpecial Focus on the Use of Mass Spectrometry and the supplementary information provided, as well as read the VOSviewer Manual, but cannot figure it out on how to make it.
I will appreciate your assistance.

I can not access web of science database. Please inform me the way to access this database.
Thanks.
Dr. Monalisha Pattnaik, India

Hello!
What exactly is the formula used in order to calculate item density?
i can see from density colors txt files that the output for each point is a value between 1 and 0, but how is that calculated?
thank you very much in advance!

please send me step by step procedure to draw the density map using web of science database from network.

Thank you for sharing your work. I have a very, very basic question: How to enlarge the font size of the software? I have a high density screen so everything looks tiny.
I am running the Windows version, but if necessary I might use Ubuntu as well.
Regards
Carlos

Dear Ludo,
Can I perform a valid co-occurrence (type of analysis) of the author keywords (unit of analysis) with only 206 articles?
Thank you

Hello,
I have a question about the citation of authors.
For example I have 625 citations, 208 total link strength and 135 links. So the focal author has citation links with 135 other authors. With some authors, the focal author has more than one citation link. This is reflected by the total link strength of 208. In total, the focal author has 208 citation links with the 135 authors with which it has citation links, right? But what do the 625 citations mean?
Thank you very much and a happy new year

What is the minimum number of documents to perform bibliometric analysis? please help me with any reference. Thanks a lot for helping along my journey.

When i writing a thesaurus file, I'm getting an error that incorrect number of columns.
I writing:
Lable replace by
Community communication
...

Dear Ludo Waltman,
I have a query regarding total link strength that has also been discussed previously in this forum. If in a co-citation map, the total link strength indicates the number of documents in which two authors/journals/documents co-occur, then what does the value of citations indicate.
Thanks in advance

Dear Ludo Waltman,
First of all, I would like to congratulate you on the great work in developing this software.
So, my question is: In january 2019, I used the VOSviewer to conduct a bibliometric analysis on a specific topic, applying the co-citation and co-occurrence analysis. However, now I am trying to update this study and I am having some difficulties in keywords co-occurrence analysis. In january, I verified that the keywords in the papers under analysis had an average publication year between 2010-2017; the database had articles published between 1993 and 2018, where most of them were recent articles. Yeasterday, I redid the keyword co-occurrence analysis developed in january ( adding to my initial database the articles that were published since january until now, and found an average publication year that range from 1940 to 2020. How is it possible since the oldest article in my database is from 1993?
I would be grateful if you could help me to solve this problem.

I am a PhD scholar at Jindal Global University, India.
I need information on interpreting the graphs. For example,
How do you calculate total link strength in different charts? What does its value really represent?
How can I obtain CSV data on the charts - for example I want to obtain the co-occurence and co-citation data of keywords and journals respectively for quantitative analysis?
The link for the AIDA booklet is not working. Can you please set it right?
Thx
Arun Saxena
India

hello, i want to know if i can use vosviewer with another platforms tham WoS, scopus. I would like to use with RCAAP.
Thank you

I want to make the co-citation analysis network with the dots as it is shown on "introduction to vosviewer" but it is coming as lines. how to do like dots are arranged in a cluster??

Dear Ludo,
Thank you for such good comment. I have edited the authors name and countries name to capital letter using this method. However, I have another problem when I open this edited map file, it did not display the lines between authors or countries. How can I fixed it?
Thank you

For the thesaurus file, if you want to merge multiple redundant terms, but one if the terms is correct, how do you do it without creating a new term? Right now it appears that a term in column one cannot appear as a replacement item in column 2.

Dear Ludo,
I wanted to run a co-citation analysis of cited references. As you know, some references appear with alternative labels. I tried to merge alternative wordings of a same reference in a map file but I could not do it. Because map file for "cited references co-citation" is not structured. When I open the map file in excel, it does not have unified column structure. Is there a way to clean/merge cited references?
Also, I wanted to merge the names of some authors with alternative wordings. I used thesaurus file but it did not change the results although I used the "replace by" column and merged them. I had alternative names of a few same authors appearing in the results. Can you please recommend a solution? Many thanks

Dear Ludo, Frist of all, congratulations for your. You dont have any idea how it is important in my master studies. Not only for me, but a lot of research colleagues. My question is about cluster. Is it possible to define and organize the words the will be show in each cluster?

Dear Ludo,
When working with large data sets, items can overlap and large items cover the smaller ones. So, some items disappear unfortunately. I wonder if it is possible with VOSviewer to manually relocate some of the disappearing items in the map.
Thanks in advance for your truly valuable efforts

Dear Mr. Waltman, I would like to ask whether the fractional counting option works as replacement for the association strength normalization approach (or other of the available weight normalization options), or whether they complement one another. Thank you in advance! And congratulations on your exceptional work!

From Co-citation analysis, I can know that a certain article has been cited 20 times or whatever the number is. But how can I know which published articles have cited that certain article?
TIA for help and cooperation.

Hello,
Where can I find the thesaurus_terms.txt file?

Dear Ludo Waltman,
Thanks for answering all the questions.
I have a question. I run a co-occurrence analysis based on title and abstract. When I choose minimum 3 occurrence, I get 186 terms. When I check them, I see some alternative use of same phrases like:
"leader mindfulness" and "leaders mindfulness",
"leader competency" and "leader skill",
"follower" and "subordinate"
"relation" and "relationship"
Is there any way that I can integrate them into one expression? I mean for instance, can I transform "leader capability" into "leader skill".
I can find and replace them in the excel file but I am not sure for the following: Are these terms ( leader capability) adjacent in the abstract and title or, are they appearing in the same title or abstract but seperate from each other (leader [............] capability), not adjacent. Can you please advice?
The following article says they used an R script to combine variants of same expressions, but I could not find how they did it.
https://doi.org/10.1016/j.leaqua.2019.06.001
I would really appreciate if you could help with this? Thanks in advance.

Hi
I have a question related to citing journals: if I am studying a specific journal's body of literature, how is it possible to find the other journals that are citing 'my' journal? I know on web of science for example how to get to that information but I was curious to see if I can also get it through VOSviewer, for example to get a map. Thx in advance

Under "Types of analysis" i dont get active for "Bibliometric coupling", "citation" and "co-citation" options. Only co-occurrence and co-authorship are active. So i cannot perform analysis. Whats the remedy please?

Dear Mr. Waltman,
I have .csv files exported from scopus and I want to conduct co-citation analysis. Although the options for analysis is inactive. Is there any way I can analyse co-citation network through .csv files.
Thank You
Anuja Joseph