Kurt R. Mattson, President of Union Legal Research in Chandler, AZ, has co-authored a research article recently published in the Fall 2017 issue of The Law Library Journal entitled, Surprising Differences: An Empirical Analysis of LexisNexis and West Headnotes in the Written Opinions of the 2009 Supreme Court Term.
Mattson wrote the article with Peter A. Hook, Head of Digital and Scholarly Services, LawArXiv Administrator, and Lecturer in Law at Cornell Law School.
Mattson and Hook empirically examined opinions of the 2009 Supreme Court Term for the number of headnotes assigned by LexisNexis and West. Additionally, Citizens United is examined in detail to determine the overlap of headnote-worthy language. Discrepancies in the number of headnotes assigned and disagreement as to headnote-worthy language call into question the rigor with which headnotes are created.
The article can be found here: https://osf.io/preprints/lawarxiv/26tvu