Disruption index (CD index)
A way to measure Scientific disruption from bibliometric data (Funk2016dynamic).
For a focal document It is defined as where is the number of documents that cite but do not cite any of ‘s references, is the number of documents that cite and some of ‘s references, and is the number of documents that cite some of ‘s references while not citing .
A review: Leibel2024what
Kim2025uncovering reviews issues of the index and proposes a new, continuous version of the measure based on Graph embedding, Embedding disruptiveness measure