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Overview of Journals

Journals also vary widely in prestige, influence, and impact, and this is reflected in the citation counts to a journal. Essential Science Indicators® provides a long-term citation ranking for journals. A comparison with short-term citation behavior can be made by consulting the Journal Citation Reports® product published by Thomson Scientific.

Counting method for papers and citations

Papers are attributed to their journal of publication. All citations received by a paper in a journal are credited to the journal of the cited paper. No restrictions are made on the citing items in compiling the citation counts, other than that they are recorded from Thomson Scientific-indexed journals only.

Time period for counts (cites, papers, cites per paper)

The time period for counts is 10 years, plus partial year counts for the current year (data is updated every two to four months). This means that any papers in the 10+ year period can be cited by any items in that same period. Database years (the actual years when items are entered into the database, which is not necessarily the publication year) are used to define the time periods.

For information on the latest data update, refer to the Notices file on the home page.

Types of items counted

Papers are defined as regular scientific articles, review articles, proceedings papers, and research notes. Letters to the editor, correction notices, and abstracts are not counted. Only Thomson Scientific-indexed journal articles, or papers, are counted.

Journals included

Journals included for ranking are drawn from the journal set categorized into 22 broad fields. Fields are defined by a unique grouping of journals with no journal being assigned to more than one field. The Multidisciplinary field contains journals such as Science and Nature, which in an article level classification, would be assigned to specific fields. This should be taken into account when analyzing the field ranking of an individual scientist, institution, or country/territory.


The average, or per paper, citation rates that are shown in the rankings can be compared to the All Years averages for the same field shown in the Baselines Average Citation Rates. They may also be compared with averages for other data elements (scientists, institutions, countries/territories) in the same field. If the All Fields category is selected the ranking of journals may be dominated by biomedical fields which tend to garner a larger number of citations than other fields.

Citation thresholds

Journals are selected for listing that meet a cumulative citation count threshold for the 10+ year period. The thresholds are based on the cutoffs given in the All Years column of the Baseline Percentiles table.

For more information about the actual thresholds used in Essential Science Indicators®, go to in-cites.

Note The absence of a journal name means the journal did not meet the citation threshold for the field to which it has been assigned.

Journal Name variations and unification

Journal names have been unified to reflect name changes or journal mergers over the ten-year period.


Journals in the rankings are numbered from 1 to N, depending on the ranking option selected with no repeated ranks for ties (ties are then ranked alphabetically). Ranking options include citations, papers, citations per paper, and journal. The citations per paper ranking normalizes to some degree for journal size.

Link to in-cites

On the rankings page, you can link to the relevant section in in-cites for any editorial commentary pertaining to a journal, if available.

Time series graphs

Clicking the Graph icon Graph icon brings up a display of time series graphs for citations, papers, and citations per paper. The time series is specific to the journal selected (or All Fields). The series is defined as a set of overlapping five year periods. For example, the period 1999 - 2003 counts papers in the database years from 1999 through 2003 and cumulates citations to these papers from all citing items from 1999 through 2003. Thus, each successive time period is defined by an identical five-year cited and a five-year citing time window to form the time series.

Note that the current year contains year-to-date data with the data being updated every two to four months.

Highly cited papers for journals (if available)

Clicking the Paper icon Paper icon brings up a list of highly cited papers for the selected journal. The highly cited papers only include those that meet a certain citation threshold specific to the field and year. The thresholds vary in order to ensure that a set fraction of the papers are designated as highly cited from the citation distribution for each field and year (see Percentiles). If no highly cited papers have been selected for the specific journal, then there is no icon.

Links from papers page

On the papers page, you can link to rankings for the institutions, countries/territories, and scientists provided the data element has been underlined in blue. These links take you to the field ranking for that data element. The paper ranking within that new data element may then be compared with its initial ranking. For example, a scientist may rank highly in a field, but the institution, country/territory, or the paper may have a lower rank.

Time series graph for papers

Clicking the Graph icon Graph icon on the papers page brings up a graph showing the number of citations received by the paper each year. Note that the current year contains year-to-date data with the data being updated every two to four months.

Ranking papers

Papers can be ranked by citations, journal title, and publication year. The default ranking is by citations (from most to least cited) with no repeated ranks for ties. The year ranking arranges papers from the most to the least current.

Web of Science

Click the Web of Science button in the paper listing to go to Web of Science® (subscription required). Web of Science provides a more detailed listing for the paper including an abstract (if available), plus other citation linking capabilities.

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This help page last modified 10/31/2007