Centre for Science and Technology Studies
Centre for Science and Technology Studies
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Leiden
Zuid Holland
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Getting Started
To get started with VOSviewer, you may want to take a look at some of the sources of information listed below.
VOSviewer book chapter
VOSviewer is discussed in detail in a recent book chapter. The chapter provides a tutorial in which the use of VOSviewer is demonstrated in a step-by-step manner. The chapter is based on VOSviewer version 1.5.5. Some of the improvements and extensions introduced in the most recent versions of VOSviewer are therefore not covered in the chapter. In addition to VOSviewer, the chapter also discusses the CitNetExplorer tool for visualizing and analyzing citation networks of publications.
VOSviewer paper
VOSviewer was originally introduced in a paper published in Scientometrics in 2010. In the meantime, VOSviewer has been improved and extended in many ways, so the paper is not fully up-to-date anymore. However, it still provides a useful introduction into the main ideas underlying VOSviewer.
Comments
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stephanie
October 11th, 2019 9:44 am
Hi all, I have a couple of questions, one related to co-occurrences and the other to the country information.
1- Is it correct to say that the co-occurrence map is 'only' using the keywords information ? It would be nice to create a co-occurrence map using title and abstract data as well, is this something I can do by creating a corpus myself? Has anyone tried it? Does that work 'well' or are there some issues?
2- Is the 'country' information, for example in the bibliographic coupling feature, related to the organization country (and not the author nationality)? For example an article authored by an author working at Berkeley University would be assigned to the USA, even if the author is not american ?
thx in advance
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Ludo Waltman
October 11th, 2019 9:47 am
1. No, this is not correct. VOSviewer supports two types of co-occurrence maps, one based on keywords and the other based on terms extracted from titles and abstracts of publications.
2. Yes, this is correct.Reply
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Juan Pablo USUGA CADAVID
October 7th, 2019 4:19 pm
I have two questions concerning the relatedness and one concerning the clusters:
1) Could you please explain me the difference between the lines and the spatial position of two words in the graph? In other words, do the lines and the spatial position (closeness) tell the same information? (strong line = close elements and weak line = far elements)
2) Do you have any paper where I can find more details about the estimation of this relatedness with the lines. If so, could you please give me the reference to read it?
3) Do you have any paper where I can find more details about the creation of clusters? If so, could you please give me the reference to read it?
Thank you in advance,
J.Reply-
Ludo Waltman
October 11th, 2019 9:13 am
1) Correct. The lines and the closeness provide approximately the same information. The proximity of two items approximately reflects the strength of the link between the two items.
2) We don't have a paper specifically on this topic.
3) See https://doi.org/10.1016/j.joi.2010.07.002 or https://arxiv.org/abs/1006.1032.Reply
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Lotus Ramana
September 30th, 2019 4:21 pm
I am using VOSviewer for text mining, and I’m having difficulty understanding how the Occurrences attribute is calculated. According to the VOSviewer manual, “In the case of full counting, the Occurrences attribute indicates the total number of occurrences of a term in all documents.” This seems simple enough, but when I create a visualization based on text data, using the full counting method, I get a map which shows a particular term with “Occurrences: 4,” and I am certain that in my corpus the term appears 15 times. Can you suggest any reasons for this discrepancy? Many thanks, in advance.Reply
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Aamir Memon
September 27th, 2019 3:06 pm
I am struggling to define the terms "link" and "link strength" in my paper. In the network visulation map for author keywords, we had 66 keywords with 479 links and a total link strength of 1338 (minimum link strength = 6, maximum link strength = 456). How do we define it in simple terms?
Thanks in advance!
Best,
AamirReply-
Ludo Waltman
September 28th, 2019 1:35 pm
Please see my response below to the question by David Sanchez. This question is similar to yours. Chapter 2 in the VOSviewer manual also explains this issue. Let me know if you need additional information.Reply
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Aamir Memon
September 29th, 2019 6:19 pm
Dear Dr. Waltman,
I had already seen the response to the question by David Sanchez and had read the description in chapter 2 as well. I would, however, be grateful to get your response to this particular situation that I discussed in my question because the description is still unclear to me.
Thank you in advance!
Best,
AamirReply-
Ludo Waltman
September 29th, 2019 7:28 pm
There are 479 pairs of keywords between which there is a co-occurrence link. Each link has a link strength, which is the number of documents in which two keywords co-occur. The sum of the link strengths equals 1338.Reply
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Aamir Memon
September 29th, 2019 9:31 pm
This means that in 66 keywords included, there were 479 pairs of keywords between which there was a co-occurrence link. For example, physical activity and sleep co-occur together making a link of co-occurrence. Is this a correct explanation?
Each link has a link strength, which is the number of documents in which two keywords co-occur. The group of keywords co-occurred in a way that that the sum of the link strengths was 1338. Is that right?
Thanks for the explanation!
Best,
AamirReply
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Deepa
September 26th, 2019 1:27 pm
Dear Dr. Ludo Waltman,
Is there any way that I can import my edited Scopus CSV excel file into VOSViewer? Currently, it is not allowing me to choose among the types of analysis i.e., by default the software is only running the co-authorship analysis.
Thanks.Reply-
Ludo Waltman
September 28th, 2019 1:25 pm
Our advice is not to edit Scopus CSV files in MS Excel. Although in principle it is possible to edit Scopus CSV files, in practice this almost always causes all kinds of problems.Reply
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Deepa
September 28th, 2019 7:00 pm
Okay.
But sir, if we require to clean the Scopus data first (to yield accurate results), can we convert the file into an excel sheet, make the desired changes and reconvert the file into csv format, before importing into VOSViewer?Reply
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Varsha
September 26th, 2019 1:13 am
I cant able to open the file and the message shows
"while reading VOSviewer thersaurus file (line:1): PTT is not a valid coloumn header)".
Kindly help me
Thanks ,
VarshaReply -
Kumar
September 22nd, 2019 7:15 pm
Dear Ludo Waltman,
Is it possible to know the source documents of keywords such that the relevant papers can be separated for literature review and analysis?Reply-
Ludo Waltman
September 22nd, 2019 10:30 pm
There currently is no easy way to obtain this information in VOSviewer. However, there is an option that you could use. When creating a keyword co-occurrence map, in the final step of the 'Create Map' wizard, a table is shown listing the keywords to be included in the map. By right-clicking on this table, it is possible to export the document-keyword relations to a file.Reply
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Kumar
September 23rd, 2019 3:10 pm
Dear Ludo Waltman,
Thank you for your immediate response. I could use the method and get needful information. I have another query. I have downloaded search results from both Web of Science and Scopus. Is there a method to develop a single keyword map from both these results. Secondly, whether the duplicate items in both the results affect the output. Is there a way to eliminate duplicates.Reply
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Lurdes
September 16th, 2019 11:26 pm
Dr. Ludo Waltman,
It's possible to know the Degree, Betweenness Centrality and Closeness Centrality in the co-citation network (Cited references).
ThanksReply-
Ludo Waltman
September 17th, 2019 12:04 am
VOSviewer does not provide centrality statistics. I personally believe they are often misinterpreted and used incorrectly. In VOSviewer, you can save your map in a GML file or in a Pajek network file. You can then perform centrality calculations in Gephi or Pajek.Reply
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xin
September 7th, 2019 1:13 am
Dear Dr. Waltman,
Just wondering is there any way to use zotero exported document and put them into VOSviewer?
Otherwise, do you know any approach that I can export zotero data into scoupus or web of science bibliography format? I could not find a way so far, but I really do not want to mannully assmble 150 citations again in scoupus to visualize it...
Thanks a lot!
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Ludo Waltman
September 8th, 2019 11:25 am
Do you have DOIs for your documents? In that case, my advice would be to export the DOIs in a plain text file, to provide this file as input to VOSviewer, and to then use the Crossref or COCI API to obtain bibliographic data for your documents. An alternative approach could be to try to export your data from Zotero in a RIS file. This RIS file can then be provided as input to VOSviewer. Exporting your data in a file in the Web of Science or Scopus file format won't be possible.Reply
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Ibtissam Zaza
September 6th, 2019 11:50 pm
Dear Dr. Waltman,
I am new to VOSviewer. I am trying to create a map based on bibliographic data. I chose that option -> read data from reference manager files -> select files "EndNote". My question, if my library is in EndNote X9, how can I download a file with the extension .enw from EndNote? If you can direct me, I highly appreciate it!
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Ibtissam Zaza
September 6th, 2019 12:02 am
Dear Dr. Waltman,
I want to conduct co-word analysis over the library that I have on my EndNote. how can I link VOSviewer to EndNote?Reply-
Niloofar Solhjoo
September 16th, 2019 10:05 pm
Hi
First, you need to export all your references from Endnote. Save it as a Text File type and your output style must be "EndNote Export". (To enable this style in your EndNote software go to: Edit-->Output styles-->Open style manager--> tick the EndNote Export and close the window).
Then open your text file in a Notepad and save as it again. this time your file extension must be like "file-name.enw" and save it as All Files type.
There you go, now you have a file with .enw extension which is supported by VOSviewer.
Reply
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Natalia K
August 22nd, 2019 10:43 am
Dear Dr. Waltman, I've got the following question. While constructing co-authorship map, is there any way to integrate the link strength directly from the data? For example, the data looks like this: A and B co-authored X articles, B and C - Y articles, A and C - Z articles. Can VOS viewer process this kind of data to construct the map? Thank you in advance!Reply
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Ludo Waltman
August 23rd, 2019 8:00 am
I am not sure if I fully understand your question. VOSviewer is indeed able to process this kind of data. This is the main purpose for which VOSviewer can be used.Reply
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NK
August 23rd, 2019 10:11 am
Thank you for your reply, and please allow me to clarify. The number of co-authored articles is already in the file - it has been calculated, so that the VOSviewer doesn't have to do it like it normally does with the files from the Scopus and other databases. My trouble is with creating the .csv file that VOSViewer could recognize and figuring out which header I should use for the column with the number of co-authored articles. For now, VOSViewer counts each of those co-authored articles as one, rather than occurring X, Y, Z times.Reply
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Ludo Waltman
August 23rd, 2019 12:52 pm
It seems you are trying to create a VOSviewer network file. For more information about these files, I recommend taking a look at the VOSviewer manual. Basically, a VOSviewer network file consists of three columns. In your case, the first two columns contain the names (or identifiers) of authors, while the third column contains the number of co-authored publications for a pair of authors. The columns don't have a header.Reply
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CONCETTA IOVINE
August 8th, 2019 11:18 pm
Hi, we are elaborate some network with your programma. We was no able to put the name in the network in capital letter. Is it possible? Thank youReply
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Jude 'Feranmi
July 29th, 2019 6:42 pm
Dear Waltman,
Please I will like to know if Vosviewer can help with constructing the raw data from the WOS database that I downloaded on country collaborations using the address.
I have about 50,000 articles I am trying to analyse and can't build the data by looking at the addreses and collaborations one after another. Is there a way Vosviewer can do this?
Thanks in advanceReply-
Ludo Waltman
July 29th, 2019 8:41 pm
What do you mean by 'constructing the raw data'?Reply
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Jude 'Feranmi
July 30th, 2019 12:13 pm
I will like to run a regression analysis using a collaboration index. But for me to calculate the index, I need to know how many instances collaboration by a country with another country occured in a particular year.
i.e a table that has a column for each country and the number of articles that the country partnered with. e.g Germany has 5 articles with Austria, 6 with Netherlands, 7 with Spain, 8 with France and so on
I assume this data is what is used to construct the map and visualisations. Is it possible for me to get the data?
Thank you sir.
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Ludo Waltman
July 30th, 2019 2:08 pm
Yes, this is possible. You need to create a co-authorship map of countries. You then need to save the map (using the 'Save' button on the 'File' tab) in a VOSviewer map file and a VOSviewer network file. The data that you are looking for can be extracted from these two files.Reply
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David Sanchez
July 25th, 2019 4:18 pm
Hello,
I struggle with the interpretation of links and link strength. E.g., when I do a citation analysis of authors, I get e.g. 700 citations, 750 links and link strength of 1200 of author X. The number of citations is derived from the database (e.g. Scopus). How are the links and total link strength derived exactly? What do the link and total link strength exactly stand for? Is it possible that an author has more links than citations?
Thanks a lot!
With best, DavidReply-
Ludo Waltman
July 26th, 2019 8:20 am
In your example, the focal author has citation links with 750 other authors. The focal author may be cited by these authors, may cite to these authors, or both. With some authors, the focal author has more than one citation link. This is reflected by the total link strength of 1200. In total, the focal author has 1200 citation links with the 750 authors with which it has citation links.Reply
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ASHISH GOSAIN
July 23rd, 2019 11:26 am
Hi,
I have a dataset on Patents granted for Bt COTTON at the USPTO FOR 2005-TO 2018. Ihave recorded the forward citations of the subs et of these Patents. Some of these are cited by Examiner and others are volunatry. Can this be visualised using VOS Viewer using an Excel File of the Data. Is there any coding required. Please consider a beginner's level in answering this question.
Thanks,
AshishReply -
Eric R
July 18th, 2019 12:17 am
For a bibliographic network visualization, is there any way to edit the author names so that they can appear in upper case or initial caps and/or without the first/middle initials? Thanks!Reply
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Ludo Waltman
July 19th, 2019 8:18 pm
Yes, this can be done, not within VOSviewer but outside. You need to save your map in a VOSviewer map file. This is a plain text file with tab-delimited columns. The file can be opened in a spreadsheet program such as MS Excel. You can then manually edit the labels of the items in your map (i.e., the author names). When you save the file and then open it again in VOSviewer, the labels will be displayed in the desired way.Reply
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Alihosein
July 16th, 2019 10:35 am
I am using vosviewer now, I want to add the thesaurus I have made to do co-ocurrence but the error appear. the error is below
error while reading vosviewer thesarus file (line 26): incorrect number of columns
I want to know what is the error and how can I fixed it?
thank youReply -
GG
July 12th, 2019 6:28 pm
Dear Ludo,
Thanks for your comments and work.
I performed a co-citation analysis (from Web of Science). I get the references (papers) with the cluster number. I export the result (save VOSViewer map file), visible with excel. Each reference has an ID.
My question is: how can I generate a file that indicates ID, authors, journals... and abstract? (my goal is to perform a lexical analysis of abstracts while keeping the cluster number).
Thanks again !Reply-
Ludo Waltman
July 13th, 2019 7:07 am
I am afraid that abstracts are not available for the references in data downloaded from Web of Science. They are available only for the documents in data downloaded from Web of Science, not for the references in these documents. Perhaps you could do a bibliographic coupling analysis instead of a co-citation analysis, since a bibliographic coupling analysis is based on the documents in your data, not on the references in these documents.Reply
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A.A.
July 11th, 2019 10:37 am
Dear all,
How can I expand my map as in adding other items to my existing map?
Thank you.Reply-
Ludo Waltman
July 12th, 2019 7:22 am
VOSviewer does not have any functionality for expanding maps. However, you can do this manually by saving your map in a VOSviewer map file and by editing this file in a spreadsheet program such as MS Excel. In Excel, you can then manually add new items to your map.Reply
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Lurdes
July 7th, 2019 3:03 am
Hello Ludo,
It's possible, to know the articles with highest co-citation frequencies?
Thank you,
Lurdes
Reply-
Ludo Waltman
July 7th, 2019 4:01 pm
When you have created a co-citation map of documents, the total link strength of a document indicates the total number of co-citations the document has with other documents included in your map.Reply
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Lurdes
July 8th, 2019 12:41 am
Thank you.
Another subject, the authors' country calculation on VOSviewer (Citation/Countries) is different from that calculated by the Web of Science, for some countries.Reply
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Cesar França
June 28th, 2019 3:17 am
Please,
How can I use the text mining functionality of VOSviewer?
Thank you!
Cesar FrancaReply -
Trang Pham
June 26th, 2019 5:18 am
Dear all,
I am very interested in your VOS viewer.
One issue I am concerned is that does your VOS viewer can run database fromWeb of Science- Thomson (all database) or only Web of Science (Core Collection)?
Hope to hear from you soon.Reply -
Jessica Bell
June 19th, 2019 3:35 pm
When creating a keyword thesaurus, I'm getting an error that there are the same terms in the label column as in the replace by column and there are not. I didn't receive this error yesterday, but am today. I have no idea what I'm doing incorrently!Reply
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Julea Shaw
June 11th, 2019 8:40 pm
When creating a keyword co-occurrence map, you are able to choose the minimum number of occurrences of a keyword in order to include it in the map. How do you know what the threshold should be to include a term?Reply
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Ludo Waltman
June 12th, 2019 7:41 am
My recommendation is to try out different thresholds to explore the effects on the selection of keywords and on the map that is obtained. In general, it is recommended to create multiple maps based on different parameter choices in order to explore the sensitivity of the results to the parameter choices. In a map, you can see for each keyword how often it occurs. In this way, you know for each keyword whether it will be included or excluded for a specific choice of the minimum number of occurrences threshold.Reply
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Andy Yeung
June 6th, 2019 10:39 am
Fractional counting of authorship: Does fractional counting affect the strength of "link" only, or can it adjust for the actual count when the map.txt is viewed in Excel? I want to check out the adjusted count, which is impossible from Web of Science's Analyze function. Thank you.Reply
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Ludo Waltman
June 8th, 2019 10:33 am
Could you please clarify your question. What do you mean by 'actual count' and 'adjusted count'?Reply
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Andy Yeung
June 8th, 2019 3:52 pm
Actual count is the count obtained by full counting. But I want to see a count that is adjusted by co-authorship. For example, if a paper is authored by both Chinese and USA authors. By full counting, China = 1 and USA = 1. By fractional counting, China = 0.5 and USA = 0.5. Can the values from the latter be found in the map.txt? I know that the link strength changes if I choose fractional counting instead of full counting, but link strength is not what I want.Reply
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Andy Yeung
June 6th, 2019 9:55 am
Hi - Is it possible to search only for publications in WoS that have an PMID? I would like to present visualizations together with data of MeSH descriptors. Hence, I am not interested in publications not indexed in PubMed.
Ultimately, I want to define a body of literature by MeSH descriptors, get their bibliometric data from WoS (or Scopus), and visualize by VOSviewer. Is that possible?Reply -
Anne Zehoul
June 5th, 2019 7:45 pm
Hello
I am a first time user of VosViewer, and got stuck in the first step : when I try to select the SCopus csv file it appears a message :
Error while reading Scopus file 'xx': IOException reading next record: java.io. IOException : (line2) invalid char between encapsulated token and delimiter.
Do you know how to fix it ?
tks a lot !Reply-
Ludo Waltman
June 5th, 2019 8:23 pm
This is a bug in the Scopus CSV export. We are in contact about this with the Scopus team at Elsevier. They are working on fixing the bug. As a temporary workaround, you could try to export only selected fields rather than all available fields. In particular, excluding abstracts from the CSV export might help.Reply
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Anne Zehoul
June 5th, 2019 11:52 pm
Thank you Ludo !Reply
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PJH
June 4th, 2019 9:42 pm
Is dimensions data downloaded and analyzed in VOSviewer or only in Dimensions.
PhilipReply -
Alex
June 4th, 2019 6:06 pm
Hi - Is it possible to automate the uploading of multiple .csv files via the 'create files based on text data' option and the 'read data from bibliographic database files' specifically? And then confirming all the following options? I've consulted section 5.1 and can't see anything, but as I'm not really familiar with command line procedures I may be missing something. So any pointers would be much appreciated.
Thanks,
Alex.Reply-
Ludo Waltman
June 4th, 2019 9:50 pm
This is indeed not possible at the moment. Perhaps we can add this feature in the future. However, I am afraid I cannot make any promises. There is a long list of features that we would like to add to the software, but unfortunately our resources are limited. Thanks for making this suggestion!Reply
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PJH
June 4th, 2019 2:36 am
We wrote a bibliometric paper using VOSviewer where the editor asked if we could confirm the results with a second database (we used Scopus). Given that in the field(s) being reviewed (management-education) Scopus coverage is much broader than WOS, I don't really see the point of this. I think it is a request from someone who doesn't really understand the relevant factors.
In any case, if we can't convince the editor otherwise, am I correct that there is no way to combine databases from Scopus and WOS together into a single analysis? The best we could do would be to run a second search in WOS and then compare the results?
Thanks.
PhilipReply-
Ludo Waltman
June 4th, 2019 3:25 am
Yes, you are right, there is no straightforward way in which data from different data sources can be combined.
By the way, instead of, or in addition to, Web of Science, you could also consider the use of Dimensions.Reply-
Katia Figueroa
August 15th, 2019 8:04 pm
Hello,
The same problem here... what do you mean by Dimensions?
Thank you
KatiaReply-
Ludo Waltman
August 15th, 2019 10:56 pm
See https://www.dimensions.ai/.Reply
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Katia Figueroa
August 15th, 2019 11:47 pm
Ludo
Thank you for your kind response, I'm looking for an article/book chapter that says: "there is no way to combine databases from Scopus and WOS together into a single analysis" as PJH posted... Could you help me with this.. please.
Thank you in advance
KatiaReply-
Ludo Waltman
August 15th, 2019 11:52 pm
I don't think such an article exists. Combining data from multiple data sources is very challenging. Without an extensive bibliometric expertise, it is not possible. However, with a deep understanding of bibliometric data sources and good access to these data sources, there are possibilities to combine data from multiple sources.Reply
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Katia Figueroa
August 16th, 2019 12:14 am
Ludo,
Do you happen to know about an article where the authors justify using only one data base (WoS or SCOPUS)?
Best
KReply-
Ludo Waltman
August 16th, 2019 8:22 am
The justification often is not made explicit, and in many cases it is probably pragmatic. Authors have access to one data source and not to another, which explains their choice of a data source. However, there is quite some bibliometric literature studying the strengths and weaknesses of different data sources. This literature could be used to make an informed and justified choice to use a particular data source.Reply
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Treshani
June 3rd, 2019 11:47 am
Hi Ludo,
Could you please tell me if there is any possible way to show two terms together when mapping based on text data (from title and abstract).
For instance, I want 'virtual reality' as a single label on the map, but my map shows 'reality' separately.
Thanks
TreshaniReply-
Ludo Waltman
June 3rd, 2019 5:13 pm
If you don't want 'reality' to be included in your map, you can use a thesaurus file to remove it. You can also use a thesaurus file to merge 'reality' and 'virtual reality', if this is what you want.
When identifying terms in titles and abstracts, VOSviewer identifies the longest possible terms. Hence, if a sentence includes the phrase 'virtual reality', this is counted as an occurrence of the term 'virtual reality', not of the term 'reality'. However, if for whatever reason the term 'virtual reality' is not included in your map, occurrences of 'virtual reality' will be counted as occurrences of 'reality'.Reply
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Pedro Silva
May 28th, 2019 7:12 pm
I have been playing around with VOSviewer and CItNet, trying to distill some insights from a search query which yielded >4900 hits in Web of Science. Among other things, I had VOSviewer generate a keyword map. Obviously, with such a large number of records I got a large interconnected map but only 5 major clusters. That is fine, but I wonder if there any simple way to modify the program so that one can retrieve (from VOSViewer) the identities of the papers which contribute to each cluster (or to a selected number of terms from a cluster. That would be tremendously helpful when preparing,e.g, a systematic review of the literature: using vosviewer to find broad subfiels, then zooming into a specific region of interest to obtain a manageable group of papers.Reply
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Ludo Waltman
May 29th, 2019 3:09 am
There currently is no easy way to accomplish this. However, when you create a map, in the final step of the 'Create Map' wizard, a table is shown listing the keywords to be included in the map. By right-clicking on this table, it is possible to export the document-keyword relations. By combining the document-keyword relations with the keyword-cluster relations (which can be obtained by saving your map in a VOSviewer map file), it is possible to find out which documents contribute to which clusters. In principle, this offers a solution to your problem, but it is not a very easy one.Reply
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Pedro Silva
May 29th, 2019 8:04 pm
I have followed your instructions and see how it can be done. Thanks! The "only" glitch is that papers are identified by number in the document-keyword file, and in a long list of documents it could be difficult to avoid mistakes when selecting them by hand afterwards.
Do you think it would be possible to include (in a future update) a simpler way to do that?Reply
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PJH
May 23rd, 2019 4:41 am
Hi
I'm looking at the feasibility of a review project and identified around 40,000 relevant documents in Scopus. Scopus would only allow export of 'citation information' for 20,000 documents at a time. So I tried that and got access to a csv file with 20K documents in it with basic info plus citations.
However, when I ran it to see what kinds of analyses I'd be able to do in VOSviewer, the only analysis available was co-author of authors. Everything else was grayed out.
What am I missing or doing wrong here? And, can you suggest a way to get this info from Scopus in a reasonably efficient way. Or would WOS be any better?
Thanks.
PhilipReply-
PJH
May 23rd, 2019 7:08 am
With some more work I figured one way to deal with this in Scopus (not sure if it's the best).
1. Identify documents (40,000 [plus)
2. Save to independent lists (Reply-
Ludo Waltman
May 23rd, 2019 9:28 am
Unfortunately, the functionality in Scopus for exporting up to 20,000 records is of limited use, since a lot of data will not be included in the resulting file. To get all relevant data, you need to use the regular export functionality of Scopus, which supports a maximum of 2,000 records. You may need to find ways to split up your search results in batches of at most 2,000 records (e.g., by making a breakdown by publication year).Reply
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giuseppe vito
May 22nd, 2019 7:21 pm
Dear Ludo,
I created an Author Keywords map with bibliographic data from Web of Science (limit: 2 occurrences).
Many Keywords obtained with Vosviewer are not present in those mentioned by the Author in the full text of the paper.
What can the explanation be?
The format of the scores in the Vosviewer map files is not numerical, whether I open them with Excel (2019) or OpenOffice (2019).
Can you help me?
Thanks in advanceReply -
Atefeh Zolfagharnasab
May 20th, 2019 9:02 am
Hi dear Ludo
You said in this article "Text mining and visualization using VOSviewer", VOSViewer can use for text mining.
There was a function In data mining that called "associated rules". Can we call the co-occurrence a branch of associated rules?Reply -
João Pildervasser
May 15th, 2019 3:37 am
Hi Ludo,
When creating a text map using data from WoS (journal: "New Phytologist", year: 2016-2019) and selecting the overlay visualization using "avg. pub. year" the year range automatically generated goes from 2017.2 to 2017.5. If I manually set it to 2016-2019 the map becomes monochromatic as if all publications are from mid-2017. What's the reason for that and is there a way to solve it? ThanksReply-
Ludo Waltman
May 17th, 2019 9:18 am
The color of a term reflects the average publication year of the publications in which the term occurs. For almost all terms, this average publication year will be somewhere in the middle of your period of analysis. This is why in your case the colors are concentrated between 2017.2 and 2017.5. You can click on the color bar to manually change the year range to 2016 and 2019. You will see that the terms then almost all have the same color, making the color coding of little use.Reply
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Dennis Lundberg
May 13th, 2019 4:03 pm
We are moving away from Oracle's Java because of the changed license terms. Instead we are deploying AdoptOpenJDK, which is a distribution of OpenJDK.
We are unable to start the downloadable executable of VOSviewer on neither Windows 10 nor MacOS X. All we get is an error message saying "Unable to run the Java runtime environment.
What can we do to run VOSviewer on OpenJDK? Is there a configuration option that we can use to tell VOSviewer which version of Java to use?Reply -
Atefeh Zolfagharnasab
May 12th, 2019 10:08 am
Hi
I had phrases that their characters were more than 20 and when map was created these phrases were not shown completely. How can I see them completely in the map?Reply -
Pedro Silva
May 8th, 2019 5:40 pm
The manual states that when extrating terms from a bibliography VOSviewer by default only considers terms which appear in more than 10 documents. Is there a possibility for the user to change this? I have searched the maual and could not find anything on thatReply
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Pedro Silva
May 8th, 2019 6:00 pm
I just discovered that those opions appear when I upload the bibliography bibliographic database format (like PubMed) but it is not available when using reference manager formats (like *ris). What is the technical reason for this?Reply
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Ludo Waltman
May 9th, 2019 12:24 pm
The option is also available for RIS files. You've probably overlooked it. PubMed and RIS files are handled in the same way by VOSviewer.Reply
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Pedro Silva
May 9th, 2019 12:50 pm
I see now that I clicked finish too soon and therefore overlloked that menu. Thanks for pointing out my error.
I am also finding trouble with thesuaurus files: I have a pubmed_results file with 4500 abstracts and around 10200 authors. around 800 of the author names are different forms of the names of the same people and therefore I made a thesaurus file . When loading it, I got several error warnings claiming that I have the same name in the two columns, though those names look to me different (e.g. utesch , tillman and utesch , tillmann). I guess there are limitations when the replce by is a substring of the label column (or the other way around, I am not sure). ANyway, I got around all of those errors but when VOSviewers shows me the terms, it still claims it has found 10200 individual authors and when plotting I still find nodes corresponding to the individual names, just as if no thesaurus file had been read. What should I do? I am sure I am making a ver stupid newbie mistake, maybe in the formatting of the thesaurus file or whatever..... :-(Reply
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Treshani
May 8th, 2019 1:41 pm
Hi Ludo,
Is there a possible way to merge Scopus (csv) and Web of science (txt) files together to build a bibliographic network.Reply -
Ying
May 7th, 2019 6:56 pm
Dear Dr. Ludo,
I am interested in investigating the theme differences in research journals and practitioner-oriented journals/magazines in my discipline. However, the articles in non-refereed journals have no abstract.
So my question is that can VOSviewer be used to analyze the keywords in non-referred journals/magazines?Reply-
Ludo Waltman
May 7th, 2019 9:15 pm
If you have access to the data required for carrying out such an analysis, I believe this should be possible.Reply
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Ying
May 8th, 2019 1:55 am
Dr. Ludo,
Thank you so much for your quick response!
I tested the keyword analysis with the magazine data (from the title and abstract field) and the results did show up like a normal term map.
One question adding to that is which part of the content was used as the source for extracting the terms when there is no abstract in the data?Reply -
Ying
May 8th, 2019 4:09 am
Dr. Ludo,
Sorry for making confusion in the last question.
I think I really want to ask is that which type of creating the map can analyze the whole text instead of the title and abstract (i.e. create a map on bibliographic data for keyword co-occurrence analysis, or create a map based on text data for term analysis)?
Thank you in advance for reading the message.Reply-
Ludo Waltman
May 8th, 2019 7:11 am
If you want to use full text data, not just titles and abstracts, you need to provide the full text data as input to VOSviewer in a so-called corpus file. In the 'Create Map' wizard, you first need to choose the option 'Create a map based on text data', followed by the option 'Read data from VOSviewer files'. Information about corpus files can be found in the VOSviewer manual.Reply
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Oguzhan Alasehir
May 4th, 2019 3:39 pm
Dear Dr. Ludo,
I need to convert thousands of txt files (containing abstracts of articles) to pure terms. Vosviewer can achieve it perfectly by applying "Create a map based on text data". However, the problem is about how to do it for thousands of times. Could you please provide a good solution for this requirement?
Best regards,Reply-
Ludo Waltman
May 4th, 2019 4:11 pm
Using the command-line parameters supported by VOSviewer (see Section 5.1 in the VOSviewer manual), it should be possible to automate this task. You will need to program a simple script for this.Reply
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Oguzhan Alasehir
May 4th, 2019 4:58 pm
Thx for quick reply.
I just tried this solution. It seems working partially. The missing part is how to export the list of terms and their occurences. The interface has an option "Export Selected Terms" when I right click. However, I couldn't find any parameter in command line.
Btw, as an alternative solution, may I find open source codes for preprocessing of my text files where I can get the same results with VOSviewer.
Best regards,Reply
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Giuseppe Vito
May 3rd, 2019 8:51 pm
Dear Ludo, MY APOLOGIES
Author Keywords map (network file *.csv or *.xlsx):
We have: weight (Links), weight (Total link strength), weight (Occurrences), score (Avg. pub. Year), score (Avg. citations).
How do you calculate score (Avg. norm. citations)?
Many thanks, sorry for the mistakes in the two previous mail
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Giuseppe Vito
May 3rd, 2019 8:46 pm
Dear Ludo,
sorry, I clarify:
Author Keywords map (network file *.csv or *.xlsx):
We have: weight (Links), weight (Total link strength), weight (Occurrences), score (Avg. pub. Year), score (Avg. citations)
How do you calculate score ?
Many thanks
Reply -
Giuseppe Vito VITO
May 3rd, 2019 8:42 pm
Dear Ludo,
Author Keywords map (network file *.csv or *.xlsx):
We have weight, weight, weight, score, score
How to calculate score ?
Many thanks
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Joe Shmoe
May 3rd, 2019 2:23 am
How is the average publication year in the overlay map calculated?Reply
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John Collis
April 30th, 2019 3:08 pm
Hello,
I have a csv file delimited by commas. When I try to import it into VOSviewer I get an error message "error while reading VOS map file (line 1) : Total is not a valid column header@. I am running on Windows 10Reply -
Atefeh Zolfagharnasab
April 30th, 2019 11:08 am
Hello
I have 2 questions:
1. When a map is created based on text data, in my density visualization, I see some words apart from other words. For example, "herbal medicine" is close to "effect" and away from "alternative medicine." Does this distance have a special meaning?
2. in first step, I created a map based on text data for "spiritual health" subject area, and in clusters I selected "traditional medicine" because there were a strong links between "alternative medicine" and "traditional medicine". then I searched for"traditional medicine" in databases and created a map for related terms about "traditional medicine" again but when map was created, "alternative medicine" had weak link with "traditional medicine". Do theses links have a special meaning?Reply-
Ludo Waltman
April 30th, 2019 1:12 pm
Regarding your first question, the distance between two terms approximately indicates their relatedness, where the relatedness of terms is measured by co-occurrences in publications. In general, the smaller the distance between two terms, the more strongly the terms are related.
I don't fully understand your second question, so I'm afraid I cannot answer that one.Reply
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Jordan Wrigley
April 29th, 2019 7:32 pm
Hello!
I'm trying to create a citation, bibliographic coupling, or co-citation map based on data from Scopus and/or Web of Science. But, the options for those mapping types are grayed-out and can not be selected no matter which file type I use. Any idea what I need to do? Is there maybe a column I should rename?
Cheers!
JordanReply