About Journal Impact Index
With regard to the IGBB website...
Journal Impact Index
for a particular article/journal is taken from the Scimago Journal & Country Rank
database. For an article published in journal J
in year Y
, the impact index used is the Scimago "Cites/Doc (2 years)" value for Y
-1; e.g., for a Nature
article published in 2018, the impact index is the "Cites/Doc (2 years)" for 2017 (i.e., 24.753). There are five exceptions which are indicated by symbols immediately following the Journal Impact Index
value or space where a value is absent:
- ‡ The "Cites/Doc (2 years)" for y-1 has not yet been released.
- † An article was published in the first year for which a "Cites/Doc (2 years)" was available. Since there is no Y-1 value, Y is used instead.
- § The article was published in a journal before that journal was indexed by the Scimago Journal & Country Rank database. In such instances, the first published "Cites/Doc (2 years)" value is used.
- λ The journal is not indexed by Scimago. Of the hundreds of articles in the IGBB database, only two are in journals not indexed by Scimago.
- δ The journal is currently in its inaugural year of publication, and thus a "Cites/Doc (2 years)" value is not available for it at present.
Until 2018, the IGBB obtained its Journal Impact Indexes
from the subscription-based Web of Science Journal Citation Reports (JCR) database compiled by Thomson Reuters. However, the JCR was purchased by Clarivate Analytics
, and Mississippi State University's subscription to JCR was not renewed. Of note, the Scimago average citations per document over a 2-year period [Cites per Doc. (2y)] values are computed using the same formula employed to determine JCR Impact Factors.
Dr. Olga Pechanova
Senior Research Associate
The IGBB is supported, in part, by the following units:
The IGBB is an HPC² member center.