30 jul. 2015

How is an academic social site populated? A demographic study of Google Scholar Citations population

José Luis Ortega
How is an academic social site populated? A demographic study of Google Scholar Citations population 
Scientometrics, 2015, 104(1):1–18 
DOI 10.1007/s11192-015-1593-7


Objectives
The principal objective of this work is to describe the growth of GSC in its initial moments (2011–2012) through a set of personal attributes such as bibliometric indicators, positions, disciplines, organizations and countries. This objective aims to make clear the biases that could appear in this population and discuss how they would affect the research evaluation.
Several research questions can be formulated from this primary objective:
• How is the growth of profiles in GSC and how can the number of profiles be estimated?
• How have the characteristics that define this population (bibliometric indicators,
position, discipline, affiliation and country) evolved during this initial moment?
• What consequences could have this distribution of profiles for research evaluation?
Methods
Quarterly samples from December 2011 to December 2012 were extracted from Google Scholar Citations to analyse the number of members, distribution of their bibliometric indicators, positions, institutional and country affiliations and the labels to describe their scientific activity.
Results
- Google Scholar Citations was growing very fast during 2012, going from 26,600 profiles in December 2011 to 187,301 in December 2012. At least from the harvested data, because our estimations suggest 236,000 profiles, which is close to 10 times of the initial size
- Most of the users are young researchers, with a starting scientific career 
- From the subject matter point of view, Google Scholar Citationsis dominated since its beginnings by researchers close to Computer Science and related disciplines. However, the last samples appreciate the emergence of researchers from Physics and Environmental Sciences and
Medicine that balance the thematic distribution of the service.
- Both country and institutional distributions exhibit evidence that this service is getting populated by waves of researchers, firstly from English-speaking countries where Harvard University and Massachusetts Institute of Technology were outstood; then from European countries and finally from emergent countries, highlighting Brazil and their Universidade of Sa˜o Paulo and Universidade Estadual Paulista.


With the fast growth of Google Scholar, the question is:  What is the situation in july 2015?



29 jul. 2015

Open access and sources of full-text articles in Google Scholar in different subject fields

Jamali, H. R., Nabavi, M. 
Open access and sources of full-text articles in Google Scholar in different subject fields. 
Scientometrics, (Online Version: 23 july 2015) 
DOI 10.1007/s11192-015-1642-2


Objectives
1. To determine the rate of full-text availability of items in GS according to disciplines.
2. To identify the sources of bibliographic information and full-text files in GS.
3. To determine any possible correlation between full-text availability, number of versions and number of citations.
Methods
Three queries were created for each of 277 minor subject categories of Scopus. The queries were searched in Google Scholar and the first ten hits for each query were analyzed.  8310 items were analyzed. Citations and patents were excluded from the results and the time frame was limited to 2004–2014.
Results
- 61.1 % of articles were accessible in full-text in Google Scholar; 
- 80.8 % of full-text articles were publisher versions
- 69.2 % of full-text articles were PDF. 
- There was a significant difference between the means of times cited of full text items and non-full-text items. 
- The highest rate of full text availability for articles belonged to life science (66.9 %). 
- Publishers’ websites were the main source of bibliographic information for non-full-text articles. 
- For full-text articles, educational (edu, ac.xx etc.) and org domains were top two sources of full text files. 
- ResearchGate was the top single website providing full-text files (10.5 % of full-text articles).


Available in

17 jul. 2015

Índice H de las Revistas Científicas Españolas según Google Scholar Metrics (2010-2014)

Nos es grato anunciar la publicación del Índice H de las revistas científicas españolas según Google Scholar Metrics (2010-2014), donde puede encontrar el impacto de las revistas científicas españolas a partir del recuento de citas que ofrece Google Scholar Metrics.
 Este producto surge a fin de superar una limitación importante de Google Scholar Metrics. A saber: A día de hoy no permite agrupar y ordenar las revistas según su país de publicación. Google se ha decantado por ofrecer sus rankings generales por lenguas (muestra las 100 que mayor impacto poseen), permitiendo solo en el caso de las revistas en inglés, rankings por áreas temáticas y disciplinas (4.618 publicaciones agrupadas en 8 categorías temáticas y 303 subcategorías). En este caso solo presenta las 20 revistas con mayor índice h. De esta opción han quedado excluidas las revistas de los otros nueve idiomas en los que Google presenta listados (chino, portugués, alemán, español, francés, japonés, holandés e italiano). Google solo ofrece directamente información de 68 revistas españolas que mayor impacto poseen. Dichas revistas figuran dentro del listado de las 100 revistas en español de mayor índice h.
Los rankings se organizan por campos científicos y disciplinas de las revistas científicas españolas que figuran en Google Scholar Metrics (GSM). Se han identificado 1069 revistas, de las que 560 son de Ciencias Sociales, 248 de Arte y Humanidades, 142 de Ciencias de la Salud y 119 de Ciencias Naturales e Ingenierías.
Puede acceder al índice pinchando en esta dirección:


Este trabajo es continuación directa de los publicados para los períodos

2009-2013
Ayllón, J.M; Martín-Martín, A.; Orduña-Malea, E.; Ruiz Pérez, R. ; Delgado López-Cózar, Emilio (2014). Índice H de las revistas científicas españolas según Google Scholar Metrics (2009- 2013). EC3 Reports, 17.  


2008-2012
 Ayllón Millán, J.M.; Ruiz-Pérez, R.; Delgado López-Cózar, E . Índice H de las revistas científicas españolas según Google Scholar Metrics (2008-2012). EC3 Reports, 7: 18 de noviembre de 2013. Accesible: 


2007-2011
Delgado López-Cózar, E.; Ayllón, JM, Ruiz-Pérez, R. (2013). Índice H de las revistas científicas españolas según Google Scholar Metrics (2007-2011). 2ª edición. EC3 Informes, 3: 9 de abril de 2013. Accesible en:


Si comparamos esta edición con las precedentes se pueden destacar los siguientes hechos: 
- Una gran estabilidad en los datos
- Un ligero crecimiento en la cobertura de revistas españolas por parte de GSM: 126 revistas más en esta edición que en la correspondiente a 2007-2011.
- Todas las áreas científicas crecen excepto en ciencias de la salud donde se constata una caída importante (84 revistas menos). Por contra, el área que más crece es Ciencias Sociales (153 revistas más).

Queremos subrayar que el objetivo último de este trabajo es comprobar la amplitud en la cobertura que posee Google Scholar Metrics de las revistas científicas españolas, en consonancia con la línea experimental abierta por el grupo de investigación EC3 dirigida a testar las posibilidades de Google Scholar y sus productos derivados para fines evaluativos.

8 jul. 2015

Identifying evidence for public health guidance: a comparison of citation searching with Web of Science and Google Scholar

Levay, P., Ainsworth, N., Kettle, R., Morgan, A. (2015). Identifying evidence for public health guidance: a comparison of citation searching with Web of Science and Google Scholar. Research Synthesis Methods, (Online Version) DOI: http://dx.doi.org/10.1002/jrsm.1158.


Aim 
To examine how effectively forwards citation searching with Web of Science (WOS) or Google Scholar (GS) identified evidence to support public health guidance published by the National Institute for Health and Care Excellence.
Method
Forwards citation searching was performed using GS on a base set of 46 publications and replicated using WOS.
Outcomes
WOS and GS were compared in terms of recall; precision; number needed to read (NNR); administrative time and costs; and screening time and costs. Outcomes for all publications were compared with those for a subset of highly important publications.
Results
The searches identified 43 relevant publications. The WOS process had 86.05% recall and 1.58% precision. The GS process had 90.7% recall and 1.62% precision. The NNR to identify one relevant publication was 63.3 with WOS and 61.72 with GS. There were nine highly important publications. WOS had 100% recall, 0.38% precision and NNR of 260.22. GS had 88.89% recall, 0.33% precision and NNR of 300.88. Administering the WOS results took 4 h and cost £88–£136, compared with 75 h and £1650–£2550 with GS.
Conclusion
WOS is recommended over GS, as citation searching was more effective, while the administrative and screening times and costs were lower.