Journal Metrics / Impact Factor
|Journal||Start Yr||Articles||Total Cites||Cites per Article||h* index||h5* index|
1. Alternative Impact Factor
Several journal metrics are calculated. The first metric is an alternative impact factor which is based on Google Scholar's citation count.
The journal impact factor (JIF) normally referred to is the proprietary journal impact factor from Thomson Reuters calculated based on the Web of Science (WOS) and published in the Journal Citation Reports ® (JCR). We call this the JCR ®JIF. DOAJ writes: "There is only one official, universally recognised impact factor that is generated by Thomson Reuters; it is a proprietary measure run by a profit making organisation. It runs against the ethics and principles of open access." This journal has no JCR®JIF, but an alternative Google-based impact factor.
Today 57 % of readers find their way to SCIRP's articles via Google Scholar. No open or proprietary database is directing so many readers to SCIRP's articles. Google Scholar is the only openly available database suitable for journal metric calculation. It has a wide coverage and is a meaningful source. For this reason, SCIRP is calculating its own Impact Factor based on Google Scholar's citation counts. Scientists are used to Thomson Reuters' way of calculating an impact factor. For this reason, SCIRP applies Thomson Reuters'(TR) algorithm as published on http://wokinfo.com/essays/impact-factor in Figure 1. This algorithm is not protected and can be used by anyone. In short: SCIRP calculates a 2-year Google-based Journal Impact Factor (2-GJIF).
With respect to all articles from this journal for the respective year:
A = total cites in 2016 = 307
B= 2015 cites to articles published in 2014 - 2015 = 82 (this is a subset of A)
C = number of articles published in 2014 - 2015 = 61
2-GJIF for 2016 = D = B/C = 82/61 = 1.34 (TR algorithm, Google citations, data
Please see also the List of Citations for OJSTA.
An impact factors for e.g. 2016 can only be published once this year is over (e.g. in 2017). At Thomson Reuters this is done when all 2015 publications have been processed. Once published, the JCR ®JIF for a given year is fixed. In contrast, a GJIF has never a fixed value. Depending on individual activities on the Internet (self-archiving and Green Open Access), some articles published Closed Access in one year may appear online only months or even years later. This has an influence on Google Scholar's citation count and makes it necessary to state the 2-GJIF for a given year always with the date the data was retrieved from Google Scholar. SCIRP may provide updates of the 2-GJIF during the year.
E = 2016 self-citations to articles published in 2014 - 2015 = 1 (this is a subset of B)
Self-Cited Rate = E/B = 1/82 = 1.2 % (definition Rousseau 1999, data March 2017)
Journal self-citations are citations to articles in the same journal. A Self-Cited Rate below 20 % is considered acceptable. A higher Self-Cited Rate than this could be explained by a journal's novel or highly specific topic, but could also reveal a journal with excessive self-citations.
Please interpret the 2-GJIF with caution:
Due to differences in the underlying database, the value calculated here for the 2-GJIF can not be compared with a JCR ®2-JIF.
Do not compare journals from different subject fields based on their JIF. Journals in fundamental subject fields tend to have higher impact factors than journals in specialized or applied subject fields.
Journal metrics should not be used to assess individual authors. Please refer instead to our article metrics provided for each paper: Number of citations from Google Scholar and number of citations from CrossRef.
h = 20 (data March 2017, based on the Google Scholar Citations)
The current h-index considers citations from the start of the journal. It is a cumulative index that grows each year. Look at the list of Top Cited Articles sorted by "Times Cited - highest to lowest". Count down the list. Stop before your counter h becomes larger than the number of citations of the article. The number h you counted up to is the h-index.
h5 = 14 (data March 2017, based on the Google Scholar Citations)
Now in 2017 we calculate the h5-index for 2016 and consider only citations of the articles that were published from 2013-2017. Counting these citations in the same manner as for the h-index yields the h5-index. The h5-index can also be calculated for journals publishing less than these 5 years, but it is hard for new journals to compete. Compare the h5-index of this journal also with what Google Scholar has calculated: The h5-index of the top ranked journals in the field of Marine Sciences & Fisheries. Admittedly, this journal may still have to grow to reach world class ranking, but which of the journals listed are Open Access?!
4. Statistics, Productivity, and Impact
Year in which journal started publishing = Y_start = 2011
Number of full years journal is publishing = Y = 9
Number of articles published since journal start = P_total = 282
Number of articles published in 2016 = P_2016 = 13
Total number of citations since journal start = C_total = 2106
Number of citations in 2016 = C_2016 = A = 307
Average number of citations per year = C_total/Y = 2106/9 = 234
Average number of citations per paper = C_total/P_total = 2106/282 = 7.5
with data from March 2017.