Hot Paper Thresholds
Hot papers are papers that receive a large number of citations soon after publication, relative to other papers of the same field and age. They are papers published in the past two years that received a number of citations in the most recent two-month period that places them in the top 0.1% of papers in the same field.
Time Period for Counts
We measure age for hot papers in two-month periods rather than years, and we only scan papers published in the last two years to see if they are receiving more citations than normal. To get a current sampling of citations, we count citations from only the most recent two-month period. We define the time periods by Early Access or publication date. The data is updated bi-monthly (six times a year).
Field and Age Variations
To correct for field variations in citation rate, each field is treated separately. Since older papers tend to be cited more than newer (just published) papers, a separate analysis is made for each two-month grouping of papers, giving a total of 12 groupings over the two-year period.
Sample Report
The following table shows ten two-month periods, beginning with the fourth period (July-August) of 2011. The most recent two-month period is 2013-1 (January-February 2013). This report reveals that a paper in the field of Chemistry is hot if it was added to Web of Science in the:
- 4th period of 2011 and received at least 14 citations in the most recent two-month period
- 2nd period of 2012, and received at least 12 citations in the most recent two-month period
- 1st period of 2013, and received at least 3 citations in the most recent two-month period
| Field | 2011-4 | 2001-5 | 2011-6 | 2012-1 | 2012-2 | 2012-3 | 2012-4 | 2012-5 | 2012-6 | 2013-1 |
|---|---|---|---|---|---|---|---|---|---|---|
| Chemistry | 14 | 11 | 12 | 11 | 12 | 9 | 8 | 6 | 4 | 3 |
When the header of the last column changes to 2013-2, different numbers can appear in some or all of the columns. Those number may be larger or smaller because only citation data from the current two-month period is used to generate the counts in all columns.
Be aware that the total number of citations received by a hot paper will likely be higher than the number shown in any one of these columns, which is only the number of citations received in the current two-month period.
Highly Cited Thresholds
The highly cited threshold is the minimum number of citations received by the top 1% of papers in the research field published in the specified year. We define the time periods by Early Access or publication date.
When the calculated threshold is two or fewer for a subject category in a given year, no paper in that category and year receives a Highly Cited designation. This low threshold decision is based on observations that only two citations is small evidence of highly cited paper status. Papers cited at low levels tend to exhibit more volatility with respect to highly cited status over subsequent ESI updates.
Sample Report
In the following report, the top 1% of papers in Physics added to Web of Science in 2010 received at least 44 citations. The top 1% of papers in Plant & Animal Science added to Web of Science in 2011 received at least 16 citations. Articles citing the 2010 papers may have been published between 2010 and 2013. Articles citing the 2011 papers may have been published between 2011 and 2013.
| Field | 2009 | 2010 | 2011 | 2012 | 2013 |
|---|---|---|---|---|---|
| Physics | 61 | 44 | 26 | 10 | 0 |
| Plant & Animal Science | 42 | 29 | 16 | 6 | 0 |