I quote from our 2009 paper:

"Google Scholar™ (GS) is considered to be superior to the ISI Web of Science (WoS) or Elsevier Scopus sources for five reasons. First, GS expands data sources beyond ISI-listed journals to include additional scholarly sources such as books, dissertations, conference papers, and non-ISI journals. Second, GS’s search and retrieval considers all authors instead of only the first listed author. Failure to recognize an author’s contribution if he is not in the first author’s position under represents the influence of that author.7 Third, GS is able to aggregate minor variations of the same publication title into a single item. Fourth, GS includes Languages Other than English (LOTE) sources that are generally not included in the WoS. And fifth, GS has superior coverage of social science and computer science compared to WoS.

On the other hand, GS includes non-scholarly citations, has uneven coverage, and under represents older publications compared to the WoS. Also, GS’s automated search process occasionally returns nonsensical results and is not updated as frequently as WoS (Harzing, 2008a). However, GS’s inclusion of non-journal sources such as books, dissertations, and conference papers; retrieval for all authors; LOTE materials; and superior coverage of information systems items make it a superior tool that should be used in future studies of this type. (Truex, et al, 2009, p. 570)."

The citations are as follows:

Harzing, A.-W. (2008a) "Google Scholar - a new data source for citation analysis," http://www.harzing.com/pop_gs.htm (2/22/08, 2008).

Truex III, D. P., Cuellar, M. J., and Takeda, H. 2009. "Assessing Scholarly Influence: Using the Hirsch Indices to Reframe the Discourse," Journal of the Association of Information Systems (10:7), pp. 560-594.

Another paper you might want to consult is:

Mingers, J., and Lipitakis, L. 2009. "Counting the Citations: A Comparison of Web of Science and Google Scholar in the Field of Management." Canterbury, UK: Kent Business School, University of Kent.

An important factor to consider beyond the database quality per se is also that, unlike JCR and Scopus, GS is free.

More information about this question

http://blog.impactstory.org/googe-scholar-profiles-fail/

I agree with your points that the GS is more comprehensive than other databases. But, it does not restrict to any set of standard journals or sources. There is no standard coverage procedure.  It covers all junks (many predatory journals fall into GS search results). Sometimes the numbers shown in search results (citations) are different from the actual citations. I do not know whether GS considers citations from blogs. But, it is free. Acuracy, quality standard, authenticity and reliablity are questionable.

Hi Guna, you are right GS includes everything it can find and is thus more comprehensive than ISI or Scopus. It is up to you to filter out those citation sources you don't want. For example if you only want academic citations, you need to remove those from practitioners, junk journals etc. 

You should not expect one set of immediately available clean data due to data quality issues. There is a substantial amount of data cleaning that you have to do in order to get to the data set you want to analyze. Just as in any form of analytics, you need to clean the data before you use it. I might even hazard a guess that the data is perhaps cleaner than you would get pulling from a information systems in a corporation.

Therefore your statement about questionable accuracy, quality, authenticity and reliability is really based on wrong expectations. Google scholar reports unfiltered what it finds (to my knowledge) and is therefore accurately, reliably and authentically reporting what it is intended to report. The quality is a result of the citation standards of the sources from which it pulls and this is where a lot of the issues come from (multiple versions of authors names, inaccurate citing of article names, dates and journals). 

There is today no one source where you can pull exactly what you want that reflects the totality of reality in terms of source citation. There are even citations to my own work that exist that are not reflected in Google Scholar. It is in my opinion simply the best available source that we have at the moment. 

GS has a broader coverage of literatiure, present in the web, than the other commercial databases. Whereas the commercial databases (WoS, Scopus) enable benchmarking researchers' publication activities at  global scale, GS could provider a better insiight  to regional or local contributions.  Clearly, comparing researchers' activities based on GS records  seems difficult  at present because of the necessary to filter the records in terms of quality/impact . Clearly, GS's biggest advantage is its free availability worldwide and lately also via the WoS portal, that allows access to the  openlly accessible content.

Cuellar & Gautam:  I agree with you patly on some points. I am not against GS. I alway support GS for its free distribution and its comprehensive coverage of documents in many languages. But, so many reserch studies have proved the fact about inacuracy, inconsistent, noisy,  false hits, etc of GS data. I have given a few examples here: 

“In addition GS retrieved the most multiple copies which included duplicates and triplicates. The study also show that all three citation resources retrieved unique citation hits of which WOS retrieved the most. The study was able to establish that GS is not yet a substitute for WOS and/or Scopus for the South African scholarly environmental sciences journals internationally accredited during the period 2004-2008. It was concluded that GS can be used as a supplementary citation resource to the fee-based citation resources WOS and Scopus.” http://ujdigispace.uj.ac.za/handle/10210/8191

“For citation analysis, Scopus offers about 20% more coverage than Web of Science, whereas Google Scholar offers results of inconsistent accuracy. PubMed remains an optimal tool in biomedical electronic research. Scopus covers a wider journal range, of help both in keyword searching and citation analysis, but it is currently limited to recent articles (published after 1995) compared with Web of Science. Google Scholar, as for the Web in general, can help in the retrieval of even the most obscure information but its use is marred by inadequate, less often updated, citation information.”

http://www.ncbi.nlm.nih.gov/pubmed/17884971

Google Scholar’s massive and diverse coverage base can sometimes make their search results noisy and full of false hits, prompting us to remember that high search accuracy is sometimes desirable over massive search recall.

http://intellogist.wordpress.com/2011/03/21/web-of-science-vs-scopus-which-is-better-part-2/

“Google offers limited and sometimes dysfunctional search options for such well-structured data.”

“Unfortunately, G-S gives a bad name to autonomous citation indexing. It shows lack of competence, and understanding of basic issues of citation indexing. G-S fails even in implementing the most basic Boolean OR operation correctly (Figure 9). Riding on the waves of the regular Google software which is great for processing the unstructured heap of billions of Web pages, G-S cannot handle even the meticulously tagged, metadata-enriched few million journal articlesgraciously offered to it by many publishers for free.”

http://www.iisc.ernet.in/currsci/nov102005/1537.pdf

Also see: http://opeconomica.files.wordpress.com/2013/08/jbr90002_1092_1096.pdf

What we can do is the data retrived from GS can be used as a supplementary (after refinement of noise) in addition to the WOS and Scopus citation data. It needs careful refinement and authentication.

Guna: Thanks for a broader coverage.

The last paragraph pointing to a supplemantary role of GS is true for someone having access to WoS or Scopus.  But, for those having no access to these commercial databases, GS should serve as a standalone source of information (of course filtering/refinement/authentication is always needed). 

I believe the time has come when we should move beyond these metrics and these should no more be treated as parameters to gauge the quality of a research work. Since most of these metrics are based on citations, as such there should be no question about which being better and the only difference lies in the coverage of journals and other publications by each indexing service. 

Even if the question would have been "how far the metrics determine the quality of research work, the way these metrics are being used as a parameter in determining so?, I would say, higher number of citations do not necessarily reflect the publication is of good quality, at the same time there is every likeliness that a good quality research work may be poorly cited.  

Besides needless to say, more the people have grown aware of the number of citations their publication have received, more they have started follow the citations their publications receive more they have are involved in increasing this number.

Dear all,

I agree that GS is important complementatry part of the scientist assessments, comparing with JCR and Scopus, but this picture seems be dimnished since:

- there is lack of standards, so it depends on discipline,

- GS appreciate also disciplines/scientists working mainly in their own language, not English, publishing in Open Access journals, electronic sources or conference proceedings - and allows to estimate their influence to science, if any is observed,

- is there possibility to assess correlations among GS, JCR and Scopus? for single scientists or whole discipline, is there any?

- is there possiibility to manipulate (=make fast growing) results in GS? it would be much easier then in JCR or Scopus?

The main cause of GS (and any other metrics) usefulness is its relevance.

What I have personally felt is that Web of Science and SCOPUS are better, in fact excellent than Google Scholar. There are number of problems yet to be resolved with Google Scholar.

unfortunately web of science is virtually weak in social and computer sciences.

and why the librarians have not developed their databases like the other databases in medical and mathematical sciences?

This is the question. In Spain we have several databaes of social sciences and himanities, but these are considered worse than the "big three" in assessing the quality of a paper. 

what do you mean? would you mind please describe it more?

thanks a lot in advance and yours.

The Ministry of Education believes preferred criterion in all fields of science the JCR, then Scopus and GSM and then all the other databases. I have attached a my article on this topic. In the field of social sciences and the humanities that is a disaster. JCR is imperfect and incomplete. The same happens to Scopus and GSM. None uses qualitative criteria. An article can be very good and receive few quotations. Another article can be very bad, but receives many quotations from the friends of the author ....

Article Prisioneros de la Bibliometría. Contra lo cuantitativo como ...

google scholar gives every xyz research paper........ can't compare it with scopus which is more authentic way to find authenic non predatory journals..........

Google Scholar covers all journals including predatory open access journals and citations in meeting abstracts. But the WoS and Scopus do not cover those dubious journals.

Thomson Reuters indexing/ impact is must for any scholar research. Google scholar and similar institutions donate indexing to all kind of journals. This journals are accepting a research paper by next day of submission. They are focusing on money and have no research......

Dear all,

I really appreciate the discussion and I think the effort may stop unethical publication.

I have many doubts about scholar publications, impact factor, dubious journals and frauds research.

In this finding I hardly welcome to all of you. I also request

Please share your views on following "Q ?" :

Should we allow Google scholar index and similar dubious institutions as research index (impact factor)?

https://www.researchgate.net/post/Should_we_allow_Google_scholar_index_and_similar_dubious_institutions_as_research_index_impact_factor

In my view, Thomson Reuters, JCR and Scopus should be considered authentic. I don't think Google scholar is better.

Dear Ramón Piloto-Rodríguez ,

I agree with your view. However, what about fraud journals? Such journals publish a paper within a day and have many types of impact factor and indexing. Hence, as per my view we should follow standard publisher (i.e. indexed by Thomson Reuters, JCR and Scopus).

Why I am against such publication? Because, There are large number of universities offering PhD degree based on such fraud publication. And based on such degree they are getting good positions and jobs, however they don't deserve. 

To stop such thing we need to do something. 

Thanks for sharing your view.

Dear Professor Ramón Piloto-Rodríguez,

Thanks for sharing your views.

I agree with you. However, There should be some standards, so we can differentiate standard and fraud journals. And Google Scholar allow any xyz journals.

Thanks ones again

Dear All,

Go for journals indexed in Web of Science or Scopus for publication of your rank. Almost all the predatory publishers also get indexed by google scholar. (Even I was misguided and unfortunately I have publications is such journals too).

 Ranking is a different concept. For scopus and web of science, generally Impact factor is considered as a measure for showing the standard of a journal.

Regarding citations, JCR and scopus will show the citation from the journals indexed in Thomson Reuters and scopus respectively. Hence, obviously the citations in google scholar will be higher as it has maximum number of journals (including many frauds) indexed in it.  So, google scholar metrics may be misleading.

Hi

a short note about this topic

best

Gil

Working Paper The indexation of scientific journals and the bibliometry: e...

Google Scholar Profile captures more citations to my work than Web of Knowledge or Scopus, automatically adds (and tracks citations for) new papers I’ve published, is better at finding citations that appear in non-English language publications, and gives me a nice fat h-index. I’m sure you find it valuable for similar reasons.

Yes I prefer Google Scholar metric to any other metric. It has wider accessibility and automatically updates your publications and citation thus providing realistic and objective h-index.

according to my experience, I have seen many researchers publishing their work in bogus paid journals who has very high acceptance rate. They can publish any authentic/unauthentic work in their journals and these journals are mostly indexed in google scholar only. So i really dont prefer those works who are not indexed in scopus or WoS.

Hi

you must however consider the way that your administration is assessing your work...

Most often our administrations only use Web of Knowledge or Scopus indexes, which are easier to handle for them, rather than Scholar which results can need some significant process to clarify between double citations, homonyms, etc...

Gil

In my opinion each database give you your profile view inside of it. No one is better than other, they are complementary ones, WoS and Scopus give you your presence in the usally understood as main trend, GS gives you your overall presence in the academic world (including prestigious, predator and grey literature). The balance among these indicators is what an evaluator or yourself should take into account

The problem is when people manipulate these metrics. In the future all these indexes will prove the merrit of Research for social impact not for self-esteem of academics. Academics should follow the "Pan Metron Ariston" , which means "Everything in moderation" https://linguaholic.com/topic/1987-famous-greek-quotations/

I would say "no". The reason is obviously related to the quality of contribution. Scopus lists higher quality papers than those in Google Scholar.

I think there is nothing to bias. As all the databases have their own rules and regulations for quality and all. So according to the research we should prefer one of it.

In my opinion, these metrics are very similar to each other. The results of their quantitative counting are not usually very different. This results from the analogous methodology and the same determinants that are taken into account during the counting of scientific achievements.

I invite you to the discussion.

Dear Prof. Fernando Quirós Fernández,

The problem that I usually face that there are some journals that claim on their sites that they are Scopus-indexed while they aren't. On the other hand, other journals hide the facts by saying some tricks like Scopus (2020) or Scopus (2013).

For instance, one of the journals says at its main portal that it is indexed in Scopus. But I don't find it on the Scopus list. I have written many emails to them, they always ignoring me!

The attached file is an Excel sheet that contains the last updated list. You can download the last version anytime by click on "Scopus source list" from the Scopus portal: https://www.scopus.com

For more information, kindly check the link below:

https://www.researchgate.net/post/How_to_know_if_a_given_journal_is_Scopus

I agree with Adelere Ezekiel Adeniran that Google Scholar is best of the best because he uses advanced AI algorithms for searching and indexing and extremely big data from publications in the world. In this regard, SCOPUS and WoS are archaic and use manual approaches. I don't agree with Usama A Ebead that "Scopus lists higher quality papers than those in Google Scholar", because SCOPUS contains a lot of scientific dust. However, even Google Scholar does not include all citations.

One of the cons of the JCR is that they do not consider the conference's proceedings. In that regard, there are several research areas in which publishing in conferences is even most recognized than publishing in some journals. Google metrics does take this into account.

Nel. es mas arrabalero y jamas en el SNI lo aceptaran..

Hi dear Abraham, Colleagues,

I am now very happy to be outside of the "big" concept of sc. metrics you discussed. This strange US-involved concept only produces multiple fabrications (non-util papers), specifically in countries like Latin America countries. They dont have any proper technology but "produce" a lot of unnecessary papers...and not industrial results... We in Russia have now very intereswting practical industrial projects. China has also rejected a personal sc. evaluation based on sc. metrics (after 2021) and Russia is on the same track!

Google Scholar is the worst metric, this is because there is no control over the author's work (there is a lot of plagiarism of authors) and in many cases, citations correspond to papers without peer review (peer review is a very important factor).