Metrics: What's in a number?

 

What's in a number?

by Dr Arpan Pradhan

Some Important Indexing Parameters

Journal Metrics

1.      Impact Factor:

ü IF=N/D (in Year 4); for (D) Documents in Year 1 and 2 with (N) number of citations of D documents in Year 3.

ü It is Year Specific

ü Requires 4-year data

ü All Documents, D (Articles in particular Journal) and Citations (N) in Web of Science

ü It is a Relative Journal Metric

2.      5 year IF:

ü IF=N/D (in Year 7); for (D) Documents in Year 1 and 5 with (N) number of citations of D documents in Year 6.

ü Same as IF

3.      CiteScore

ü 5th year Publication

ü CiteScore=Citations/Documents (in 4 Years)

4.      IC Value

ü Core WoS and Scopus               4.5

ü ESCI and Scopus                        3.5

+

ü Additional One database            3

ü Additional Two database            5

+

ü Survival Year = Y                      log(Y)

 

Author Metrics

5.      h-index

ü Graph; X-Axis = Articles,  Y-Axis=Citations

ü Arrange in Descending Order of Citations

ü Find the Number that describes:

ü “Maximum h such that h articles are cited at least h times each.”

6.      m-index

ü m-index = h-index/ (No. of Years of Existence of the Author)

ü Acts as a Normalizing factor, for h-index

7.      g-index

ü Maximum ‘g’ such that the top ‘g’ articles are cited a total of g2 times

ü Acts as a Normalizing factor, for h-index

8.      i10 index

ü Number of articles that are cited at least 10 times

ü by Google

9.      h5 index and h5-median

ü Maximum ‘h’ such that ‘h’ articles published in last 5 years are cited at least h times each

ü h index of last five years

ü Median of these 5 years is “h5-median”

 

Disadvantages of Indexing Parameters taken under Study

Journal Metrics

1.    Impact Factor:

ü It is Year Specific and does not count the total citations of a journal

2.      5 Year Impact Factor:

ü It is Year Specific and does not count the total citations of a journal

ü Advantage over IF, is that it takes 5-year Citations

3.      CiteScore

Relationship

Calculation of Journal Metrics: Advances in Water Resources

https://www.journals.elsevier.com/advances-in-water-resources

1.      Impact Factor:                      4.016 (2019)

2.      5 Year Impact Factor:          4.277 (2019)

3.      IC Value:                              4.5+5+log(43)=11.13           (1977 to 2020)

4.      CiteScore:                            7.6 (2019)


Calculation of Author Metrics: Arpan Pradhan


1.      h-index  = 4

2.      m-index  = 4/7 (i.e. 2014 to 2020) = 0.57

3.      g-index  = 5

4.      i10 index = 0

5.      h5 index = 3

6.      h5-Median = 2 (Median value of citations)


These indexing parameters provide only some information about the journal or the authors, and in no way provides a holistic view of the quality of the journal nor the author.

In the case of Journal metrics, CiteScore provides some justification to the Journal, as the citations for the last 5 years is taken into consideration. Whereas the other two popular metrics, IF and 5year IF, although reliable in some sense, considers citations of that particular year.

As a researcher, I believe citation of an article should have higher weightage than the journal in which it is published and over a period rather than just for a single year.

Hence, similar to 5-year IF, I would propose a metric where the citations of a journal for a 5 year period are also considered, or at least the average of the last 5 years of IF values.

As far as the author metric is concerned, I would suggest a combination of the different metric would provide an overall idea about the quality of publications done by an individual author. In my opinion, a combination of m-index and i10-index could be provided with an overall perspective, as m-index normalizes the h-index values for different authors with respect to the years of active publications and i10-index with provide a quantitative perspective as to how many publications have been cited more than 10 times. If the i10-index is substantially high, authors can also be compared based on g-index as well.


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