Emerging Topic
An Emerging Topic is identified by two components: 1) a core of closely related papers, and 2) a frontier of recently published papers that cite a paper in the core. Core papers are highly cited papers published in the last 5 years. They are clustered together if they are frequently co-cited by the same publications. A period of rapid citation activity around the core papers signifies there is something happening in that realm of research. This use of the citation network means that an Emerging Topic provides an intuitive, powerful, and ever-evolving way to identify contemporary topics of the highest interest spanning the entire published literature.
To be considered an Emerging Topic, the following must be true:
- There must be a minimum of 3 and a maximum of 25 core papers
- The average publication year for core papers must not exceed 5 years
- The average publication year for co-citing papers must not exceed 2.5 years
It is possible for a paper to appear in multiple Emerging Topics, but it is rare.
Generative AI is used to assign a title that accurately represents the papers within an emerging topic cluster. The topics are updated monthly to capture the latest trends and research developments.
Core Paper
A core paper is a highly cited paper ranking in the top 1% by citations received in the same field, year of publication, and document type and published within the past 5 year. The Leiden algorithm is used to cluster papers into coherent clusters. Core papers are clustered together if frequently co-cited by the same publications.
Co-citing Paper
A co-citing paper is a paper that cites two or more of the core papers. The average publication year for co-citing papers must be 2.5 years or less.
Interdisciplinarity Index
The Interdisciplinarity Index measures how broadly an emerging research topic integrates ideas from different fields. This index is calculated by examining the variety of Web of Science categories assigned to the cited papers of both the core and co-citing papers. These cited papers represent the knowledge sources that the emerging topic builds upon. A higher diversity in the Web of Science categories of these cited papers indicates greater interdisciplinarity.
The interdisciplinarity score ranges from 0 to 1. A score of 0 indicates that the cited papers are all within the same Web of Science category, showing no interdisciplinarity. A score of 1 indicates that the cited papers are evenly distributed across different Web of Science categories, showing maximum interdisciplinarity.
The index is calculated using Normalized Shannon Entropy, formulated as follows:
I(topic) = −∑n(pilog(pi)) / log(n)
Where:
- pi is the proportion of cited papers in Web of Science category i
- n is the total number of Web of Science categories (currently 254)
- The denominator, log(n), normalizes the score to a range between 0 and 1
This method ensures the Interdisciplinarity Index reflects how well an Emerging Topic integrates diverse ideas from various fields by analyzing the cited knowledge sources of core and co-citing papers.
In the figure below, the Emerging Topic has an Interdisciplinarity Index of 0.80, while the average for emerging topics in the same primary category is 0.55, indicating this Emerging Topic has a relatively high level of interdisciplinarity compared to related topics.
Mean Publication Year
The Mean Publication Year is the average year of publication for all papers (both core and co-citing) within an emerging topic. Only papers from the last 5 full years, plus the current year to date, can be included in an emerging topic.
Mean Co-Citing Publication Year
The Mean Co-Citing Publication year is the average publication year for all co-citing papers with an emerging topic. The average publication year for co-citing papers must not exceed 2.5 years.
Papers
Papers is the total number of core and co-citing papers conforming the Emerging Topic. Some papers can be both core and co-citing, so the sum of both metrics might not correspond to the total papers.
Primary Category
Each Emerging Topic is assigned a primary category. The primary category comes from the 254 Web of Science subject categories. The assigned primary category is the Web of Science subject category that appears most frequently across all papers within an Emerging Topic.
Secondary Category
If at least 25% of papers within an Emerging Topic are assigned to a second Web of Science subject category, that category will appear as a Secondary Category.
Subject Groups
Users can browse Emerging Topics by the 21 subject groups from JCR.
Emerging Topic Category
An Emerging Topic Category is a high-level grouping of related emerging topics, designed to provide a broader thematic organization of research trends. Each category contains multiple emerging topics that share conceptual similarities, enabling exploration of research trends at both granular (topic) and aggregated (category) levels.
The categories are formed using advanced clustering techniques applied to the sentence embeddings of emerging topic titles. In total, there are 25 Emerging Topic Categories, each representing a significant research domain. Categories are exclusive, meaning that an emerging topic can belong to only one category.
Unlike emerging topics, which are updated monthly, emerging topic categories are updated annually to reflect long-term shifts in research trends and themes.
Examples of Emerging Topic Categories include:
- Machine learning and AI applications
- Advanced materials engineering
- Environmental and climate impacts
- Global health and disease trends
- Nanotechnology in drug delivery
- Education, cognitive science, and technology
- Social and political dynamics
Refer to the complete list of categories in the Emerging Topics Research Area Schema documentation for further details.