research methodology in law

Legal Research Strategy

Preliminary analysis, organization, secondary sources, primary sources, updating research, identifying an end point, getting help, about this guide.

This guide will walk a beginning researcher though the legal research process step-by-step. These materials are created with the 1L Legal Research & Writing course in mind. However, these resources will also assist upper-level students engaged in any legal research project.

How to Strategize

Legal research must be comprehensive and precise.  One contrary source that you miss may invalidate other sources you plan to rely on.  Sticking to a strategy will save you time, ensure completeness, and improve your work product. 

Follow These Steps

Running Time: 3 minutes, 13 seconds.

Make sure that you don't miss any steps by using our:

• Legal Research Strategy Checklist

If you get stuck at any time during the process, check this out:

• Ten Tips for Moving Beyond the Brick Wall in the Legal Research Process, by Marsha L. Baum

Understanding the Legal Questions

A legal question often originates as a problem or story about a series of events. In law school, these stories are called fact patterns. In practice, facts may arise from a manager or an interview with a potential client. Start by doing the following:

• Read anything you have been given
• Analyze the facts and frame the legal issues
• Assess what you know and need to learn
• Note the jurisdiction and any primary law you have been given
• Generate potential search terms

Jurisdiction

Legal rules will vary depending on where geographically your legal question will be answered. You must determine the jurisdiction in which your claim will be heard. These resources can help you learn more about jurisdiction and how it is determined:

• Legal Treatises on Jurisdiction
• LII Wex Entry on Jurisdiction

This map indicates which states are in each federal appellate circuit:

Getting Started

Once you have begun your research, you will need to keep track of your work. Logging your research will help you to avoid missing sources and explain your research strategy. You will likely be asked to explain your research process when in practice. Researchers can keep paper logs, folders on Westlaw or Lexis, or online citation management platforms.

Organizational Methods

Tracking with paper or excel.

Many researchers create their own tracking charts.  Be sure to include:

• Search Date
• Topics/Keywords/Search Strategy
• Citation to Relevant Source Found
• Save Locations
• Follow Up Needed

Consider using the following research log as a starting place: 

• Sample Research Log

Tracking with Folders

Westlaw and Lexis offer options to create folders, then save and organize your materials there.

• Lexis Advance Folders
• Westlaw Edge Folders

Tracking with Citation Management Software

For long term projects, platforms such as Zotero, EndNote, Mendeley, or Refworks might be useful. These are good tools to keep your research well organized. Note, however, that none of these platforms substitute for doing your own proper Bluebook citations. Learn more about citation management software on our other research guides:

• Guide to Zotero for Harvard Law Students by Harvard Law School Library Research Services Last Updated Sep 12, 2023 363 views this year

Types of Sources

There are three different types of sources: Primary, Secondary, and Tertiary.  When doing legal research you will be using mostly primary and secondary sources.  We will explore these different types of sources in the sections below.

Secondary sources often explain legal principles more thoroughly than a single case or statute. Starting with them can help you save time.

Secondary sources are particularly useful for:

• Learning the basics of a particular area of law
• Understanding key terms of art in an area
• Identifying essential cases and statutes

Consider the following when deciding which type of secondary source is right for you:

• Scope/Breadth
• Depth of Treatment
• Currentness/Reliability

For a deep dive into secondary sources visit:

• Secondary Sources: ALRs, Encyclopedias, Law Reviews, Restatements, & Treatises by Catherine Biondo Last Updated Apr 12, 2024 5889 views this year

Legal Dictionaries & Encyclopedias

Legal dictionaries.

Legal dictionaries are similar to other dictionaries that you have likely used before.

• Black's Law Dictionary
• Ballentine's Law Dictionary

Legal Encyclopedias

Legal encyclopedias contain brief, broad summaries of legal topics, providing introductions and explaining terms of art. They also provide citations to primary law and relevant major law review articles.  

Here are the two major national encyclopedias:

• American Jurisprudence (AmJur) This resource is also available in Westlaw & Lexis .
• Corpus Juris Secundum (CJS)

Treatises are books on legal topics.  These books are a good place to begin your research.  They provide explanation, analysis, and citations to the most relevant primary sources. Treatises range from single subject overviews to deep treatments of broad subject areas.

It is important to check the date when the treatise was published. Many are either not updated, or are updated through the release of newer editions.

To find a relevant treatise explore:

• Legal Treatises by Subject by Catherine Biondo Last Updated Apr 12, 2024 5387 views this year

American Law Reports (ALR)

American Law Reports (ALR) contains in-depth articles on narrow topics of the law. ALR articles, are often called annotations. They provide background, analysis, and citations to relevant cases, statutes, articles, and other annotations. ALR annotations are invaluable tools to quickly find primary law on narrow legal questions.

This resource is available in both Westlaw and Lexis:

• American Law Reports on Westlaw (includes index)
• American Law Reports on Lexis

Law Reviews & Journals

Law reviews are scholarly publications, usually edited by law students in conjunction with faculty members. They contain both lengthy articles and shorter essays by professors and lawyers. They also contain comments, notes, or developments in the law written by law students. Articles often focus on new or emerging areas of law and may offer critical commentary. Some law reviews are dedicated to a particular topic while others are general. Occasionally, law reviews will include issues devoted to proceedings of panels and symposia.

Law review and journal articles are extremely narrow and deep with extensive references. 

To find law review articles visit:

• Law Journal Library on HeinOnline
• Law Reviews & Journals on LexisNexis
• Law Reviews & Journals on Westlaw

Restatements

Restatements are highly regarded distillations of common law, prepared by the American Law Institute (ALI). ALI is a prestigious organization comprised of judges, professors, and lawyers. They distill the "black letter law" from cases to indicate trends in common law. Resulting in a “restatement” of existing common law into a series of principles or rules. Occasionally, they make recommendations on what a rule of law should be.

Restatements are not primary law. However, they are considered persuasive authority by many courts.

Restatements are organized into chapters, titles, and sections.  Sections contain the following:

• a concisely stated rule of law,
• comments to clarify the rule,
• hypothetical examples,
• explanation of purpose, and
• exceptions to the rule  

To access restatements visit:

• American Law Institute Library on HeinOnline
• Restatements & Principles of the Law on LexisNexis
• Restatements & Principles of Law on Westlaw

Primary Authority

Primary authority is "authority that issues directly from a law-making body."   Authority , Black's Law Dictionary (11th ed. 2019).   Sources of primary authority include:

• Constitutions
• Statutes 

Regulations

Access to primary legal sources is available through:

• Bloomberg Law
• Free & Low Cost Alternatives

Statutes (also called legislation) are "laws enacted by legislative bodies", such as Congress and state legislatures.  Statute , Black's Law Dictionary (11th ed. 2019).

We typically start primary law research here. If there is a controlling statute, cases you look for later will interpret that law. There are two types of statutes, annotated and unannotated.

Annotated codes are a great place to start your research. They combine statutory language with citations to cases, regulations, secondary sources, and other relevant statutes. This can quickly connect you to the most relevant cases related to a particular law. Unannotated Codes provide only the text of the statute without editorial additions. Unannotated codes, however, are more often considered official and used for citation purposes.

For a deep dive on federal and state statutes, visit:

• Statutes: US and State Codes by Mindy Kent Last Updated Apr 12, 2024 4284 views this year
• 50 State Surveys

Want to learn more about the history or legislative intent of a law?  Learn how to get started here:

• Legislative History Get an introduction to legislative histories in less than 5 minutes.
• Federal Legislative History Research Guide

Regulations are rules made by executive departments and agencies. Not every legal question will require you to search regulations. However, many areas of law are affected by regulations. So make sure not to skip this step if they are relevant to your question.

To learn more about working with regulations, visit:

• Administrative Law Research by AJ Blechner Last Updated Apr 12, 2024 763 views this year

Case Basics

In many areas, finding relevant caselaw will comprise a significant part of your research. This Is particularly true in legal areas that rely heavily on common law principles.

Running Time: 3 minutes, 10 seconds.

Unpublished Cases

Up to  86% of federal case opinions are unpublished. You must determine whether your jurisdiction will consider these unpublished cases as persuasive authority. The Federal Rules of Appellate Procedure have an overarching rule, Rule 32.1  Each circuit also has local rules regarding citations to unpublished opinions. You must understand both the Federal Rule and the rule in your jurisdiction.

• Federal and Local Rules of Appellate Procedure 32.1 (Dec. 2021).
• Type of Opinion or Order Filed in Cases Terminated on the Merits, by Circuit (Sept. 2021).

Each state also has its own local rules which can often be accessed through:

• State Bar Associations
• State Courts Websites

First Circuit

• First Circuit Court Rule 32.1.0

Second Circuit

• Second Circuit Court Rule 32.1.1

Third Circuit

• Third Circuit Court Rule 5.7

Fourth Circuit

• Fourth Circuit Court Rule 32.1

Fifth Circuit

• Fifth Circuit Court Rule 47.5

Sixth Circuit

• Sixth Circuit Court Rule 32.1

Seventh Circuit

• Seventh Circuit Court Rule 32.1

Eighth Circuit

• Eighth Circuit Court Rule 32.1A

Ninth Circuit

• Ninth Circuit Court Rule 36-3

Tenth Circuit

• Tenth Circuit Court Rule 32.1

Eleventh Circuit

• Eleventh Circuit Court Rule 32.1

D.C. Circuit

• D.C. Circuit Court Rule 32.1

Federal Circuit

• Federal Circuit Court Rule 32.1

Finding Cases

Headnotes show the key legal points in a case. Legal databases use these headnotes to guide researchers to other cases on the same topic. They also use them to organize concepts explored in cases by subject. Publishers, like Westlaw and Lexis, create headnotes, so they are not consistent across databases.

Headnotes are organized by subject into an outline that allows you to search by subject. This outline is known as a "digest of cases." By browsing or searching the digest you can retrieve all headnotes covering a particular topic. This can help you identify particularly important cases on the relevant subject.

Running Time: 4 minutes, 43 seconds.

Each major legal database has its own digest:

• Topic Navigator (Lexis)
• Key Digest System (Westlaw)

Start by identifying a relevant topic in a digest.  Then you can limit those results to your jurisdiction for more relevant results.  Sometimes, you can keyword search within only the results on your topic in your jurisdiction.  This is a particularly powerful research method.

One Good Case Method

After following the steps above, you will have identified some relevant cases on your topic. You can use good cases you find to locate other cases addressing the same topic. These other cases often apply similar rules to a range of diverse fact patterns.

• in Lexis click "More Like This Headnote"
• in Westlaw click "Cases that Cite This Headnote"

to focus on the terms of art or key words in a particular headnote. You can use this feature to find more cases with similar language and concepts.  ​

Ways to Use Citators

A citator is "a catalogued list of cases, statutes, and other legal sources showing the subsequent history and current precedential value of those sources.  Citators allow researchers to verify the authority of a precedent and to find additional sources relating to a given subject." Citator , Black's Law Dictionary (11th ed. 2019).

Each major legal database has its own citator.  The two most popular are Keycite on Westlaw and Shepard's on Lexis.

• Keycite Information Page
• Shepard's Information Page

Making Sure Your Case is Still Good Law

This video answers common questions about citators:

For step-by-step instructions on how to use Keycite and Shepard's see the following:

• Shepard's Video Tutorial
• Shepard's Handout
• Shepard's Editorial Phrase Dictionary
• KeyCite Video Tutorial
• KeyCite Handout
• KeyCite Editorial Phrase Dictionary

Using Citators For

Citators serve three purposes: (1) case validation, (2) better understanding, and (3) additional research.

Case Validation

Is my case or statute good law?

• Parallel citations
• Prior and subsequent history
• Negative treatment suggesting you should no longer cite to holding.

Better Understanding

Has the law in this area changed?

• Later cases on the same point of law
• Positive treatment, explaining or expanding the law.
• Negative Treatment, narrowing or distinguishing the law.

Track Research

Who is citing and writing about my case or statute?

• Secondary sources that discuss your case or statute.
• Cases in other jurisdictions that discuss your case or statute.

Knowing When to Start Writing

For more guidance on when to stop your research see:

• Terminating Research, by Christina L. Kunz

Automated Services

Automated services can check your work and ensure that you are not missing important resources. You can learn more about several automated brief check services.  However, these services are not a replacement for conducting your own diligent research .

• Automated Brief Check Instructional Video

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• Last Updated: Sep 21, 2023 2:56 PM
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• > Handbook on Legal Methodology
• > Introduction

Book contents

• Frontmatter
• Words of Gratitude
• 1 Introduction
• 2 Research objectives
• 3 Research objectives and their methodological features
• 4 Research objectives and overall methodological features
• 5 A practical guide on research objectives and methodological features
• Bibliography

1 - Introduction

Published online by Cambridge University Press:  22 February 2022

“La recherche en droit ou sur le droit n’est pas en quête de méthodes, mais elle est en quête d’identité quant à ses méthodes.”

NEED FOR AN EXPLICIT LEGAL METHODOLOGY

Legal scholarship is one of the oldest academic disciplines and the study of law has been passed on from generation to generation as an implicit “ savoir faire.” This means that during their education legal students learned how to find, analyze, apply and improve the law without explicitly considering the methodological choices they make throughout this process. Moreover, it was presumed that all legal scholars understood the methodology of legal research, making its explicit clarification and justification unnecessary. Due to the absence of an explicit methodological tradition, handbooks and literature on legal methodology did not exist. Therefore “the conventions, informal praxis, requirements and rules of play of academic legal research remain largely unwritten.”

The lack of an explicit legal methodology made it difficult for legal scholars to explain their research praxis to scholars from other academic disciplines. The last decade this has become problematic because of the growing interdisciplinary collaboration at universities and the increased importance of external funding, often granted by mixed experts panels. Due to this, legal scholars have become more aware of the importance of an explicit methodology.

Despite an increased awareness, the reflection of legal scholars on methodology was too often limited to their own personal research experiences. Only occasionally the methodological identity of legal scholarship was studied from an empirical point of view. In order to address this lacuna, a PhD project was designed to empirically explore the methodological features of legal scholarship. Essential to the project was a meta-methodological study of 45 Dutch-language PhDs on social security law defended at a Flemish or Dutch Law Faculty between 1971 and 2015. The results of the meta-study were used to complete and refine the existing, but limited literature on legal methodology.

The PhD project aimed to design an explicit methodological framework for legal scholarship. Such methodological framework lists on the one hand the research objectives legal scholars can pursue in their research, and on the other hand their methodological features .

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• Introduction
• Lina Kestemont
• Book: Handbook on Legal Methodology
• Online publication: 22 February 2022
• Chapter DOI: https://doi.org/10.1017/9781839702389.002

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Research Methods in Law

DOI link for Research Methods in Law

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Explaining in clear terms some of the main methodological approaches to legal research, the chapters in this edited collection are written by specialists in their fields, researching in a variety of jurisdictions.

Covering a range of topics from Feminist Approaches to Law and Economics, each contributor addresses the topic of ‘lay decision makers in the legal system’ from their particular methodological perspective, explaining how they would approach the issue and discussing the suitability of their particular method. This focus on one main topic allows the reader to draw comparisons between methods with relative ease.

The broad range of contributors makes Research Methods in Law well suited to an international audience, and it is ideal reading for PhD students in law, undergraduate dissertation students in law, LL.M Research students and early year researchers.

TABLE OF CONTENTS

Chapter | 7  pages, introduction, chapter 1 | 32  pages, doctrinal research, chapter 2 | 26  pages, socio-legal studies, chapter 3 | 20  pages, doing empirical research, chapter 4 | 17  pages, legal research in the humanities, chapter 5 | 19  pages, legal history, chapter 6 | 24  pages, comparative law and its methodology, chapter 7 | 24  pages, critical legal ‘method’ as attitude, chapter 8 | 24  pages, economic analysis of law, or economically informed legal research, chapter 9 | 17  pages, the master’s tools, chapter 10 | 28  pages, law and anthropology.

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Methodology in Legal Research

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Please note you do not have access to teaching notes, intersection of generative artificial intelligence and copyright: an indian perspective.

Journal of Science and Technology Policy Management

ISSN : 2053-4620

Article publication date: 9 July 2024

The main objective of this study is to present a compact overview analysis of intellectual property laws, specifically copyright-related provisions applicable to generative artificial intelligence (GenAI) in the Indian context.

Design/methodology/approach

The paper adopts a qualitative research methodology that is grounded in secondary sources of information. The data were gathered from the Scopus database for a systematic literature review.

GenAI technology has given rise to numerous questionable issues within the domain of intellectual property that need resolution in the form of policy solutions. Based on the findings of this paper, it can be deduced that Indian copyright laws are not adequate for addressing the rights pertaining to AI and its creations and outputs. Different countries like the United States, European Union and China have approached the regulation and protection of AI-generated content within the realm of copyright law in different ways. The future of law, as it has been established thus far, seems to be on a path of substantial evolution.

Practical implications

The study has implications for policymakers globally as there is a need to create feasible policy solutions that can efficiently safeguard against risks stemming from large language models (LLMs) and other GenAI models, while also promoting innovation, technical advancement and adoption.

Originality/value

The paper discusses the copyright-related issues in GenAI technology in the context of an emerging economy, India.

• Artificial intelligence
• Legal framework
• Large language models

Vig, S. (2024), "Intersection of generative artificial intelligence and copyright: an Indian perspective", Journal of Science and Technology Policy Management , Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/JSTPM-08-2023-0145

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Research on a distributed cooperative guidance law for obstacle avoidance and synchronized arrival in uav swarms.

1. Introduction

1.1. related works, 1.2. a brief summary of our work, 2. fixed-wing uav dynamics and guidance control system modeling, 2.1. six-dof fixed-wing uav dynamic model, 2.2. integrated guidance and control model for uav, 3. design of distributed guidance and control algorithms for obstacle avoidance and impact time control, 3.1. design of an itcg law based on dynamic inversion control method.

• The speed of the UAV is constant;
• The field of view constraints of each UAV are not considered;
• The target or assembly position remains unchanged;

3.2. Design of an Obstacle Avoidance Guidance Law Based on the Improved APF Method

3.3. architecture of a two-layer time synchronization algorithm based on distributed negotiation.

4. Simulation Verification

4.1. initial condition set, 4.2. simulation results analysis, 5. conclusions, author contributions, data availability statement, conflicts of interest, abbreviations.

• Yang, Y.; Xiong, X.; Yan, Y. UAV Formation Trajectory Planning Algorithms: A Review. Drones 2023 , 7 , 62. [ Google Scholar ] [ CrossRef ]
• Jeon, I.S.; Lee, J.I.; Tahk, M.J. Impact-time-control guidance law for anti-ship missiles. IEEE Trans. Control Syst. Technol. 2006 , 14 , 260–266. [ Google Scholar ] [ CrossRef ]
• Jeon, I.S.; Lee, J.I.; Tahk, M.J. Homing Guidance Law for Cooperative Attack of Multiple Missiles. J. Guid. Control Dyn. 2010 , 33 , 275–280. [ Google Scholar ] [ CrossRef ]
• Enjiao, Z.; Chao, T.; Wang, S.; Yang, M. An Adaptive Parameter Cooperative Guidance Law for Multiple flight vehicles. In Proceedings of the AIAA Atmospheric Flight Mechanics Conference, Dallas, TX, USA, 22–26 June 2015. [ Google Scholar ]
• Sinha, A.; Kuma, R.S.R.; Mukherjee, D. Cooperative integrated guidance and control design for simultaneous interception. Aerosp. Sci. Technol. 2022 , 120 , 107262. [ Google Scholar ] [ CrossRef ]
• Liz, H.; Dingz, T. Robust cooperative guidance law for simultaneous arrival. IEEE Trans. Control Syst. 2019 , 27 , 1360–1367. [ Google Scholar ]
• Li, K.; Wang, J.; Lee, C.H.; Zhou, R.; Zhao, S. Distributed cooperative guidance for multivehicle simultaneous arrival without numerical singularities. J. Guid. Control. Dyn. 2020 , 43 , 1365–1373. [ Google Scholar ] [ CrossRef ]
• Sujit, P.; Ghose, D. Search using multiple UAVs with flight time constraints. IEEE Trans. Aerosp. Electron. Syst. 2004 , 40 , 491–509. [ Google Scholar ] [ CrossRef ]
• Ueno, S.; Kwon, S.J. Optimal reconfiguration of UAVs in formation flight. In Proceedings of the SICE Annual Conference 2007, Takamatsu, Japan, 17–20 September 2007; pp. 2611–2614. [ Google Scholar ]
• Aggarwal, R.; Soderlund, A.A.; Kumar, M. Multi-UAV Path Planning in a Spreading Wildfire. In Proceedings of the AIAA Scitech 2021 Forum, Virtual, 11–22 January 2021; p. 0866. [ Google Scholar ]
• Karaman, S.; Frazzoli, E. Sampling-based Algorithms for Optimal Motion Planning. Int. J. Robot. Res. 2011 , 30 , 846–894. [ Google Scholar ] [ CrossRef ]
• Lee, D.; Shim, D.H. Path planner based on bidirectional Spline-RRT* for fixed-wing UAVs. In Proceedings of the 2016 International Conference on Unmanned Aircraft Systems (ICUAS), Arlington, VA, USA, 7–10 June 2016; pp. 77–86. [ Google Scholar ]
• Qureshi, A.H.; Ayaz, Y. Intelligent bidirectional rapidly-exploring random trees for optimal motion planning in complex cluttered environments. Robot. Auton. Syst. 2015 , 68 , 1–11. [ Google Scholar ] [ CrossRef ]
• Cao, H.; Zhang, H.; Liu, Z.; Zhou, Y.; Wang, Y. UAV route planning based on improved particle swarm optimization algorithm. Flight Dyn. 2024 , 42 , 29–35. [ Google Scholar ]
• Cao, Y.; Wei, W.; Bai, Y.; Qiao, H. Multi-base multi-UAV cooperative reconnaissance path planning with genetic algorithm. Clust. Comput. 2019 , 22 , 5175–5184. [ Google Scholar ] [ CrossRef ]
• Sun, L. Path planning of mobile robot based on improved ant colony algorithm. In Proceedings of the IEEE 11th Joint International Information Technology and Artificial Intelligence Conference, Chongqing, China, 8–10 December 2023; pp. 985–989. [ Google Scholar ]
• Cekmez, U.; Ozsiginan, M.; Sahingoz, O.K. Multi-UAV path planning with parallel genetic algorithms on CUDA architecture. In Proceedings of the 2016 on Genetic and Evolutionary Computation Conference Companion, Denver, CO, USA, 24–29 July 2016; pp. 1079–1086. [ Google Scholar ]
• Binol, H.; Bulut, E.; Akkaya, K.; Guvenc, I. Time optimal multi-UAV path planning for gathering its data from roadside units. In Proceedings of the 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), Chicago, IL, USA, 27–30 August 2018; pp. 1–5. [ Google Scholar ]
• Harounabadi, M.; Bocksberger, M.; Mitschele-Thiel, A. Evolutionary path planning for multiple UAVs in message ferry networks applying genetic algorithm. In Proceedings of the 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Bologna, Italy, 9–12 September 2018; pp. 1–7. [ Google Scholar ]
• Li, L.; Gu, Q.; Liu, L. Research on path planning algorithm for multi-UAV maritime targets search based on genetic algorithm. In Proceedings of the 2020 IEEE International Conference on Information Technology, Big Data and Artificial Intelligence (ICIBA), Chongqing, China, 6–8 November 2020; pp. 840–843. [ Google Scholar ]
• Cai, Y.; Xi, Q.; Xing, X.; Gui, H.; Liu, Q. Path planning for UAV tracking target based on improved A-star algorithm. In Proceedings of the 2019 1st International Conference on Industrial Artificial Intelligence (IAI), Shenyang, China, 23–27 July 2019; IEEE: Piscataway, NJ, USA, 2019; pp. 1–6. [ Google Scholar ]
• Yuan, X. Research on the limitations of UAV path planning based on artificial potential field method. In Proceedings of the 2022 9th International Forum on Electrical Engineering and Automation (IFEEA 2022), Zhuhai, China, 4–6 November 2022; IEEE: Piscataway, NJ, USA, 2022; pp. 619–622. [ Google Scholar ]
• Phadke, A.; Medrano, F.A.; Chu, T.; Sekharan, C.N.; Starek, M.J. Modeling Wind and Obstacle Disturbances for Effective Performance Observations and Analysis of Resilience in UAV swarms. Aerospace 2024 , 11 , 237. [ Google Scholar ] [ CrossRef ]
• Verma, S.C.; Li, S.; Savkin, A.V. A Hybrid Global/Reactive Algorithm for Collision-Free UAV Navigation in 3D Environments with Steady and Moving Obstacles. Drones 2023 , 7 , 675. [ Google Scholar ] [ CrossRef ]
• Wu, Y.; Gou, J.; Hu, X.; Huang, Y. A new consensus theory-based method for formation control and obstacle avoidance of UAVs. Aerosp. Sci. Technol. 2020 , 107 , 106332. [ Google Scholar ] [ CrossRef ]
• Wu, Y.; Xu, S.; Dai, W.; Lin, L. Heuristic position allocation methods for forming multiple UAV formations. Eng. Appl. Artif. Intell. 2023 , 118 , 105654. [ Google Scholar ] [ CrossRef ]
• Bassolillo, S.R.; D’Amato, E.; Notaro, I.; Blasi, L.; Mattei, M. Decentralized Mesh-Based Model Predictive Control for Swarms of UAVs. Sensors 2020 , 20 , 4324. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Chevet, T.; Vlad, C.; Stoica, C.; Zhang, Y. Decentralized Model Predictive Control for UAV Formation Deployment and Reconnaissance with Multiple Outgoing Agents. J. Intell. Robot. Syst. 2020 , 97 , 155–170. [ Google Scholar ] [ CrossRef ]
• Beard, R.W.; McLain, T.W. Small Unmanned Aircraft: Theory and Practice ; National Defense Industry Press: Beijing, China, 2012. (In Chinese) [ Google Scholar ]
• Chen, H.; Chen, H.; Liu, Q. Multi-UAV 3D formation path planning based on improved artificial potential field. J. Syst. Simul. 2020 , 32 , 414. [ Google Scholar ]

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Liu, X.; Li, D.; Wang, Y.; Zhang, Y.; Zhuang, X.; Li, H. Research on a Distributed Cooperative Guidance Law for Obstacle Avoidance and Synchronized Arrival in UAV Swarms. Drones 2024 , 8 , 352. https://doi.org/10.3390/drones8080352

Liu X, Li D, Wang Y, Zhang Y, Zhuang X, Li H. Research on a Distributed Cooperative Guidance Law for Obstacle Avoidance and Synchronized Arrival in UAV Swarms. Drones . 2024; 8(8):352. https://doi.org/10.3390/drones8080352

Liu, Xinyu, Dongguang Li, Yue Wang, Yuming Zhang, Xing Zhuang, and Hanyu Li. 2024. "Research on a Distributed Cooperative Guidance Law for Obstacle Avoidance and Synchronized Arrival in UAV Swarms" Drones 8, no. 8: 352. https://doi.org/10.3390/drones8080352

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Addressing AI in insurance sector contracts

AI is increasingly at the forefront for the insurance sector, as methods to tackle fraud, manage claims and improve customer service are developed. In terms of how these developments are addressed in the contracts that underpin such arrangements there are significant issues to bear in mind. This is particularly relevant for the thriving Insurtech ecosystem in Israel, where startups are leading the way in innovative AI applications.

Contracts involving AI still take the form of a technology contract under which services are being provided for specified outcomes or outputs. But there are some key concepts that warrant further consideration and that demand agility in contract drafting. With AI, we are working with complex technology that is autonomous and adaptive. And the “black box” nature of AI, where inputs and internal processes remain invisible to the user, means that is harder to monitor AI in comparison to non-AI technologies.

Taking a few key concepts in turn that impact AI-related contracts for the insurance sector, we consider how to address these from a contractual perspective.

Regulatory requirements

Insurance sector specific regulatory requirements and guidelines for outsourcing, material third party arrangements and cloud continue to be relevant to contracts involving AI. In the UK this includes the PRA Supervisory Statement on outsourcing and third party risk management and, in Europe, the EIOPA Guidelines on outsourcing to cloud service providers. As a general rule, if the contract falls within the remit of these regulatory requirements, it is necessary to consider them regardless of whether or not AI is involved.

With the implementation deadlines for the EU AI Act now looming, solutions will also need to be compliant with the new, broad-reaching legislation to avoid a costly and difficult procurement.

There is a need to assess the accuracy and service commitments that the provider is willing to offer. Often this is an assumption that computers, including AI systems, are inherently reliable – or at least more reliable than humans.

But AI models can produce “hallucinations”, or unexpected results (for example due to bias or limitations in the underlying data). So, before using an AI solution it is important to understand:

• the reliability of the training data;
• whether the tool has been subject to independent evaluations and auditing to verify the tool’s accuracy;
• to what extent the service provider will accept liability for errors caused by the AI solution; and
• the remedies that might be available in the event of any such errors, e.g. a commitment to retrain the model or to provide financial compensation.

Free to use tools are unlikely to come with any accuracy commitments, however. It is therefore important to understand the intended use cases involving AI and ensure that appropriate ring fencing and checks and balances are in place in the contract.

Exit and Lock in

Many organisations already look to the big tech providers for a range of enterprise and cloud services across their organisation. Utilising AI solutions from a provider that you are already heavily dependent upon will therefore further increase the risk of a technical lock in with that provider. It is therefore important to think about your exit strategy from the outset and how easily and how quickly you could move away from the provider in question.

And, as regulators are increasingly focussed on operational resilience and concentration risk, again the regulatory aspect must not be overlooked.

IP considerations

Perhaps one of the most important contractual aspects to consider is intellectual property. It is important to really understand the different types of IP at play, and who owns these and where responsibility lies. There will be IP in:

• the data used to train the model;
• the data inputted when using the model;
• the outcomes or analysis that is created through use of the model; and
• improvements to the AI, especially through a customer’s use of the model.

In each case it is important to think about who owns the IP and the extent to which the other party is entitled to use it. In most cases providers will insist on owning improvements to the AI model. But this can lead to unexpected consequences.

If the solution is trained on or further learns from your organisation’s own data, but the service provider owns the improvements to the model, this could mean that they are able to provide the improved model to their other clients which could give away a competitive advantage.

This can arise following proof of concept stages, where there can be less focus given that the trial is often limited both in terms of scope and duration. It is necessary to be careful at that stage therefore as the consequences may have longer lasting and significant effects.

On a similar note, it is important to think about the confidentiality aspects, particularly in respect of large language models. Potentially confidential information could be being inputted, including that of third parties to whom duties of confidentiality are owed. Does the AI contract expressly prevent uploaded information being retained or accessed by unauthorised third parties?

And finally, consider the risk of third party IP infringement. The provenance of full training data sets for many generative AI models may be unknown, and so this – and especially the content generated by the AI – may infringe the rights of others. What protection does the contract offer in respect of any third party infringement claims?

Liability is an evolving market and a common position (that may be seen in cloud contracts, for example) has not yet emerged. For standardised products, low levels of liability can be expected, with broad exclusions and little scope for negotiation. Generally speaking, liability positions are very one sided in favour of the supplier at the moment, but the potential exposure could be significant. The usual contractual approaches to liability, e.g. specifying a percentage of fees paid, are unlikely to come anywhere near compensating you for the potential losses. Think about that risk reward balance – is the business benefit to using the AI worth the potential exposure in the event of a catastrophic failure?

Restrictions on use

Many contracts may specify lots of restrictions as to how the product can be used. If you want to use AI solutions broadly, especially as part of a transformation programme, it is important to understand the solution and the restrictions that the provider has imposed and assess these against the intended use cases.

Reporting and audit

As AI technology develops, AI can be difficult to explain and understand, which makes dealing with oversight and control in the contract more challenging. Putting the onus on the supplier to have authorised quality assured systems and controls and a pro-active obligation to notify when things go wrong so that there is sufficient time to implement mitigating steps to reduce the impact of the issue could be an effective approach in addressing this challenge.

As contractual approaches to addressing the challenges and opportunities to deploying AI develop, above all it is important to apply a risk-based approach and keep in mind the principles summarised above. A carefully considered contract with sufficient flexibility – where possible to negotiate – will reduce risk and ensure that the huge opportunities offered by AI to the insurance sector can be successfully leveraged.

Filed under

• IT & Data Protection
• Artificial intelligence
• Confidential information
• Generative AI

Organisations

• European Insurance and Occupational Pensions Authority
• EU Artificial Intelligence Act

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Microcracking Process Characterization and Failure Time Prediction of Three Typical Rocks upon Uniaxial Compression Based on Acoustic Emission Activity

• Original Paper
• Published: 31 July 2024

Cite this article

• Caiyuan Fan 1 ,
• Jinfeng Liu   ORCID: orcid.org/0000-0002-6444-9427 1 , 2 , 3 &
• Fanbao Meng 1  

Mechanical stability of pillars is crucial for the safety of underground engineering. Understanding the failure process of rock pillars upon uniaxial compression may help predict its failure. This study investigates the failure process of sandstone, coal and granite under uniaxial compression using acoustic emission (AE) monitoring. A developed AE method, i.e., microcrack cumulative summation curve method, was applied to identify whether tensile or shear microcracks dominated during rock deformation to failure. This method was validated through Brazilian and direct shear tests. Our results showed that a) sandstone samples experienced shear faulting failure with AE analysis indicating an initial dominance of tensile microcracks, followed by shear microcracks, likely due to grains movements and intra- and inter-granular microcrack development; b) granite samples exhibited tensile failure, with transgranular microcracks developing along the axial compression direction, intense wing microcracks, and a potential transition from tensile to shear microcracking dominating process as indicated by AE analysis; c) coal samples displayed mixed shear-tensile failure, possibly dominated by the orientation of calcite veins where microcracks initiated, developed and coalesced, as suggested by AE and microstructure analysis. Using the power-law singularity theory for failure warning, our analysis demonstrated that lateral strain and AE count can accurately predict failure times for sandstone (15 ~ 22% early) and granite (8 ~ 12% early) samples. However, this method is less effective for coal samples due to their discontinuous failure processes. Our research highlights that combining microcrack development with failure prediction analyses effectively reveals physical failure processes in typical rocks, offering practical application for mining engineering.

A verified AE microcrack cumulative summation curve method was applied to reveal the failure process of rock materials.

Microcracking behavior for sandstone, coal and granite under uniaxial compression was analyzed to reveal likely mechanisms for failure modes.

Lateral strain and AE count are effective parameters for early warning and failure time prediction of rocks via power-law singularity theory.

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The data used and/or analyzed in this study are available from the corresponding author on reasonable request.

Aggelis DG (2011) Classification of cracking mode in concrete by acoustic emission parameters. Mech Res Commun 38:153–157. https://doi.org/10.1016/j.mechrescom.2011.03.007

Article   Google Scholar  

Amann F, Ündül Ö, Kaiser PK (2014) Crack initiation and crack propagation in heterogeneous sulfate-rich clay rocks. Rock Mech Rock Eng 47:1849–1865. https://doi.org/10.1007/s00603-013-0495-3

ASTM (2014) Designation D7012–14: standard test methods for compressive strength and elastic moduli of intact rock core specimens under varying states of stress and temperatures. ASTM Int West Conshohocken. https://doi.org/10.1520/D7012-14E01

Basu A, Mishra DA, Roychowdhury K (2013) Rock failure modes under uniaxial compression, Brazilian, and point load tests. Bull Eng Geol Environ 72:457–475. https://doi.org/10.1007/s10064-013-0505-4

Bell AF, Greenhough J, Heap MJ, Main IG (2011) Challenges for forecasting based on accelerating rates of earthquakes at volcanoes and laboratory analogues. Geophys J Int 185:718–723. https://doi.org/10.1111/j.1365-246X.2011.04982.x

Cartwright-Taylor A, Mangriotis M-D, Main IG et al (2022) Seismic events miss important kinematically governed grain scale mechanisms during shear failure of porous rock. Nat Commun 13:6169. https://doi.org/10.1038/s41467-022-33855-z

Article   CAS   Google Scholar  

Dong L, Chen Y, Sun D, Zhang Y (2021) Implications for rock instability precursors and principal stress direction from rock acoustic experiments. Int J Min Sci Technol 31:789–798. https://doi.org/10.1016/j.ijmst.2021.06.006

Du K, Li X, Tao M, Wang S (2020) Experimental study on acoustic emission (AE) characteristics and crack classification during rock fracture in several basic lab tests. Int J Rock Mech Min Sci 133:104411. https://doi.org/10.1016/j.ijrmms.2020.104411

Esterhuizen GS, Dolinar DR, Ellenberger JL, Prosser LJ (2011) Pillar and roof span design guidelines for underground stone mines. National Institute for Occupational Safety and Health, Pittsburgh, USA

Google Scholar  

Fan C, Meng F, Liu J (2023) Characterization of brittle failure modes of rock under uniaxial compression using acoustic emission. Acta Sci Nat Univ Sunyatseni 62:14–24 (in Chinese)

Feng X, Xiao Y, Feng G et al (2019) Study on the development process of rockbursts. Chin J Rock Mech Eng. https://doi.org/10.13722/j.cnki.jrme.2019.0103

Geranmayeh Vaneghi R, Ferdosi B, Okoth AD, Kuek B (2018) Strength degradation of sandstone and granodiorite under uniaxial cyclic loading. J Rock Mech Geotech Eng 10:117–126. https://doi.org/10.1016/j.jrmge.2017.09.005

Grosse C, Ohtsu M (eds) (2008) Acoustic emission testing–basics for research–applications in civil engineering, 1st edn. Springer, Berlin Heidelberg, Berlin, Heidelberg

Gudmundsson A (2011) Rock fractures in geological processes. Cambridge University Press, Cambridge

Book   Google Scholar  

Gutenberg B, Richter CF (1942) Earthquake magnitude, intensity, energy, and acceleration. Bull Seismol Soc Am 32:163–191. https://doi.org/10.1785/BSSA0320030163

Gutenberg B, Richter CF (1944) Frequency of earthquakes in California. Bull Seismol Soc Am 34:185–188. https://doi.org/10.1785/BSSA0340040185

Hao S, Wang HY, Xia MF et al (2007) Relationship between strain localization and catastrophic rupture. Theor Appl Fract Mech 48:41–49. https://doi.org/10.1016/j.tafmec.2007.04.006

Hao S, Rong F, Lu M et al (2013) Power-law singularity as a possible catastrophe warning observed in rock experiments. Int J Rock Mech Min Sci 60:253–262. https://doi.org/10.1016/j.ijrmms.2012.12.004

Hao S, Zhang B-J, Tian J-F, Elsworth D (2014) Predicting time-to-failure in rock extrapolated from secondary creep. J Geophys Res Solid Earth 119:1942–1953. https://doi.org/10.1002/2013JB010778

Hao S, Liu C, Lu C, Elsworth D (2016) A relation to predict the failure of materials and potential application to volcanic eruptions and landslides. Sci Rep 6:27877. https://doi.org/10.1038/srep27877

He M, Ren F, Liu D, Zhang S (2021) Experimental study on strain burst characteristics of sandstone under true triaxial loading and double faces unloading in one direction. Rock Mech Rock Eng 54:149–171. https://doi.org/10.1007/s00603-020-02272-3

Ju Y, Xi C, Zhang Y et al (2018) Laboratory in situ CT observation of the evolution of 3d fracture networks in coal subjected to confining pressures and axial compressive loads: a novel approach. Rock Mech Rock Eng 51:3361–3375. https://doi.org/10.1007/s00603-018-1459-4

Lei XL, Kusunose K, Rao MVMS et al (2000) Quasi-static fault growth and cracking in homogeneous brittle rock under triaxial compression using acoustic emission monitoring. J Geophys Res Solid Earth 105:6127–6139. https://doi.org/10.1029/1999JB900385

Lei XL, Masuda K, Nishizawa O et al (2004) Detailed analysis of acoustic emission activity during catastrophic fracture of faults in rock. J Struct Geol 26:247–258. https://doi.org/10.1016/S0191-8141(03)00095-6

Li L, Lee PKK, Tsui Y et al (2003) Failure process of granite. Int J Geomech 3:84–98. https://doi.org/10.1061/(ASCE)1532-3641(2003)3:1(84)

Li Y, Yang S-Q, Liu Z-L et al (2022b) Study on mechanical properties and deformation of coal specimens under different confining pressure and strain rate. Theor Appl Fract Mech 118:103287. https://doi.org/10.1016/j.tafmec.2022.103287

Li S, Huang Z, Yang D et al (2024) Study of the acoustic characteristics and evolution of the failure mode of yellow sandstone under uniaxial compression. Rock Mech Rock Eng 57:1059–1078. https://doi.org/10.1007/s00603-023-03637-0

Li S, Yang D, Huang Z et al (2022a) Acoustic emission characteristics and failure mode analysis of rock failure under complex stress state. Theor Appl Fract Mech. https://doi.org/10.1016/j.tafmec.2022.103666

Lin Q, Mao D, Wang S, Li S (2018) The influences of mode II loading on fracture process in rock using acoustic emission energy. Eng Fract Mech 194:136–144. https://doi.org/10.1016/j.engfracmech.2018.03.001

Lockner DA (1993) The role of acoustic emission in the study of rock fracture. Int J Rock Mech Min Sci Geomech Abstr 30:883–899. https://doi.org/10.1016/0148-9062(93)90041-B

Lockner DA, Byerlee JD, Kuksenko V et al (1991) Quasi-static fault growth and shear fracture energy in granite. Nature 350:39–42. https://doi.org/10.1038/350039a0

Lockner DA, Moore DE, Reches Z (1992) Microcrack interaction leading to shear fracture. OnePetro, USA

Luo G, Qi S, Zheng B (2022) Rate effect on the direct shear behavior of granite rock bridges at low to subseismic shear rates. J Geophys Res Solid Earth. https://doi.org/10.1029/2022JB024348

Martin CD, Chandler NA (1994) The progressive fracture of Lac du Bonnet granite. Int J Rock Mech Min Sci Geomech Abstr 31:643–659. https://doi.org/10.1016/0148-9062(94)90005-1

Menéndez B, Zhu W, Wong T-F (1996) Micromechanics of brittle faulting and cataclastic flow in Berea sandstone. J Struct Geol 18:1–16. https://doi.org/10.1016/0191-8141(95)00076-P

Meng F, Ge H, Yan W et al (2016) Effect of saturated fluid on the failure mode of brittle gas shale. J Nat Gas Sci Eng 35:624–636. https://doi.org/10.1016/j.jngse.2016.09.008

Muñoz-Ibáñez A, Delgado-Martín J, Herbón-Penabad M, Alvarellos-Iglesias J (2021) Acoustic emission monitoring of mode I fracture toughness tests on sandstone rocks. J Pet Sci Eng 205:108906. https://doi.org/10.1016/j.petrol.2021.108906

Ohno K, Ohtsu M (2010) Crack classification in concrete based on acoustic emission. Constr Build Mater 24:2339–2346. https://doi.org/10.1016/j.conbuildmat.2010.05.004

Paterson MS, Wong T (2005) Experimental Rock Deformation — The Brittle Field, 2nd edn. Springer-Verlag, Berlin/Heidelberg

Rodríguez P, Celestino TB (2019) Application of acoustic emission monitoring and signal analysis to the qualitative and quantitative characterization of the fracturing process in rocks. Eng Fract Mech 210:54–69. https://doi.org/10.1016/j.engfracmech.2018.06.027

Sinha S, Walton G (2021) Integration of three-dimensional continuum model and two-dimensional bonded block model for studying the damage process in a granite pillar at the Creighton Mine, Sudbury, Canada. J Rock Mech Geotech Eng 13:275–288. https://doi.org/10.1016/j.jrmge.2020.06.011

Tapponnier P, Brace WF (1976) Development of stress-induced microcracks in Westerly Granite. Int J Rock Mech Min Sci Geomech Abstr 13:103–112. https://doi.org/10.1016/0148-9062(76)91937-9

Triantis D (2018) Acoustic emission monitoring of marble specimens under uniaxial compression. Precursor phenomena in the near-failure phase. Procedia Struct Integr 10:11–17. https://doi.org/10.1016/j.prostr.2018.09.003

Triantis D, Kourkoulis SK (2018) An alternative approach for representing the data provided by the acoustic emission technique. Rock Mech Rock Eng 51:2433–2438. https://doi.org/10.1007/s00603-018-1494-1

Tuncay E, Hasancebi N (2009) The effect of length to diameter ratio of test specimens on the uniaxial compressive strength of rock. Bull Eng Geol Environ 68:491. https://doi.org/10.1007/s10064-009-0227-9

Ullah B, Zhou Z, Cai X et al (2023) Failure prediction and microcracks development based on acoustic emission and energy evolution for different rocks treated with freeze–thaw weathering. Bull Eng Geol Environ 82:471. https://doi.org/10.1007/s10064-023-03485-w

Wang C (2014) Identification of early-warning key point for rockmass instability using acoustic emission/microseismic activity monitoring. Int J Rock Mech Min Sci 71:171–175. https://doi.org/10.1016/j.ijrmms.2014.06.009

Wu B, Qiao L, Guan S et al (2021) Study on size effect of uniaxial compression tests of small size rock samples. Chin J Rock Mech Eng 40:856–873 (in Chinese)

Xue J, Hao S, Wang J et al (2018) The Changeable Power Law Singularity and its Application to Prediction of Catastrophic Rupture in Uniaxial Compressive Tests of Geomedia. J Geophys Res Solid Earth 123:2645–2657. https://doi.org/10.1002/2018JB015591

Yang lei, (2018) A study on the critical power-law singularity acceleration precursor of catastrophe damage and the method of prediction. Yanshan University, M.S.

Yao Q, Chen T, Tang C et al (2019) Influence of moisture on crack propagation in coal and its failure modes. Eng Geol 258:105156. https://doi.org/10.1016/j.enggeo.2019.105156

Zhang Z-H, Deng J-H (2020) A new method for determining the crack classification criterion in acoustic emission parameter analysis. Int J Rock Mech Min Sci 130:104323. https://doi.org/10.1016/j.ijrmms.2020.104323

Zhang Q, Zhang X-P (2017) A numerical study on cracking processes in limestone by the b-value analysis of acoustic emissions. Comput Geotech 92:1–10. https://doi.org/10.1016/j.compgeo.2017.07.013

Zhang J-Z, Wu W-T, Zhou X-P (2023) On the predictability of localization instabilities of quasibrittle materials from accelerating rates of acoustic emission. Eng Fract Mech 289:109455. https://doi.org/10.1016/j.engfracmech.2023.109455

Zhang J-Z, Zhou X-P (2020) Forecasting catastrophic rupture in brittle rocks using precursory AE time series. J Geophys Res Solid Earth. https://doi.org/10.1029/2019JB019276

Zhang J-Z, Zhou X-P (2023) Integrated acoustic-optic-mechanics (AOM) multi-physics field characterization methods for a crack: Tension vs. shear. Eng Fract Mech. https://doi.org/10.1016/j.engfracmech.2023.109339

Zhao G, Su G, Hu S, Huang J (2022a) A recognition method of cracking types for hard rock based on microseisms tests. J Exp Mech 37:107–117 (in Chinese)

Zhao Z, Yang G, Li G, Zhang K (2022b) Effects of the Length-Diameter ratio on the dissipation energy in the process of rock deformation and failure. Energy Rep 8:13369–13375. https://doi.org/10.1016/j.egyr.2022.10.003

Zhu J, Deng J, Chen F, Wang F (2022) Failure analysis of water-bearing rock under direct tension using acoustic emission. Eng Geol 299:106541. https://doi.org/10.1016/j.enggeo.2022.106541

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Acknowledgements

This research was jointly funded by the National Natural Science Foundation of China (Grant No. 41802230, 42293350, and 42293354) and the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2021A1515012202).

National Natural Science Foundation of China, 42293354, Jinfeng LIU, 41802230, Jinfeng LIU, 42293350, Jinfeng LIU, Basic and Applied Basic Research Foundation of Guangdong Province, 2021A1515012202, Jinfeng LIU.

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Caiyuan Fan, Jinfeng Liu & Fanbao Meng

Guangdong Provincial Key Lab of Geodynamics and Geohazards, Sun Yat-Sen University, Zhuhai, 519082, China

Jinfeng Liu

Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519082, China

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Fan, C., Liu, J. & Meng, F. Microcracking Process Characterization and Failure Time Prediction of Three Typical Rocks upon Uniaxial Compression Based on Acoustic Emission Activity. Rock Mech Rock Eng (2024). https://doi.org/10.1007/s00603-024-04093-0

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DOI : https://doi.org/10.1007/s00603-024-04093-0

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12 Qualitative Legal Research: A Methodological Discourse

• Published: January 2020
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Qualitative legal research aims to study things in their natural settings, understand and interpret their social realities and provide inputs on various aspects of social life. It focuses on people’s feelings, perceptions, and experiences. It differs from quantitative research in matters of nature of data, theoretical basis, and kinds of tools employed for data collection. The combination of two methods brings synergy. Worthy features of qualitative legal research consist of description of social setting, interpretation of social data, verification of assumptions, and evaluation of policies. Its steps include framing of specific questions, choice of data collection tools, sampling, data collection, analysis, and interpretation. This method allows for a mature understanding of the problematic world.

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A New Use for Wegovy Opens the Door to Medicare Coverage for Millions of People with Obesity

Juliette Cubanski , Tricia Neuman , Nolan Sroczynski , and Anthony Damico Published: Apr 24, 2024

The FDA recently approved a new use for Wegovy (semaglutide), the blockbuster anti-obesity drug, to reduce the risk of heart attacks and stroke in people with cardiovascular disease who are overweight or obese. Wegovy belongs to a class of medications called GLP-1 (glucagon-like peptide-1) agonists that were initially approved to treat type 2 diabetes but are also highly effective anti-obesity drugs. The new FDA-approved indication for Wegovy paves the way for Medicare coverage of this drug and broader coverage by other insurers. Medicare is currently prohibited by law from covering Wegovy and other medications when used specifically for obesity. However, semaglutide is covered by Medicare as a treatment for diabetes, branded as Ozempic.

What does the FDA’s decision mean for Medicare coverage of Wegovy?

The FDA’s decision opens the door to Medicare coverage of Wegovy, which was first approved by the FDA as an anti-obesity medication. Soon after the FDA’s approval of the new use for Wegovy, the Centers for Medicare & Medicaid Services (CMS) issued a memo indicating that Medicare Part D plans can add Wegovy to their formularies now that it has a medically-accepted indication that is not specifically excluded from Medicare coverage . Because Wegovy is a self-administered injectable drug, coverage will be provided under Part D , Medicare’s outpatient drug benefit offered by private stand-alone drug plans and Medicare Advantage plans, not Part B, which covers physician-administered drugs.

How many Medicare beneficiaries could be eligible for coverage of Wegovy for its new use?

Of these 3.6 million beneficiaries, 1.9 million also had diabetes (other than Type 1) and may already have been eligible for Medicare coverage of GLP-1s as diabetes treatments prior to the FDA’s approval of the new use of Wegovy.

Not all people who are eligible based on the new indication are likely to take Wegovy, however. Some might be dissuaded by the potential side effects and adverse reactions . Out-of-pocket costs could also be a barrier. Based on the list price of $1,300 per month (not including rebates or other discounts negotiated by pharmacy benefit managers), Wegovy could be covered as a specialty tier drug, where Part D plans are allowed to charge coinsurance of 25% to 33%. Because coinsurance amounts are pegged to the list price, Medicare beneficiaries required to pay coinsurance could face monthly costs of $325 to $430 before they reach the new cap on annual out-of-pocket drug spending established by the Inflation Reduction Act – around $3,300 in 2024, based on brand drugs only, and $2,000 in 2025. But even paying $2,000 out of pocket would still be beyond the reach of many people with Medicare who live on modest incomes . Ultimately, how much beneficiaries pay out of pocket will depend on Part D plan coverage and formulary tier placement of Wegovy.

Further, some people may have difficulty accessing Wegovy if Part D plans apply prior authorization and step therapy tools to manage costs and ensure appropriate use. These factors could have a dampening effect on use by Medicare beneficiaries, even among the target population.

When will Medicare Part D plans begin covering Wegovy?

Some Part D plans have already announced that they will begin covering Wegovy this year, although it is not yet clear how widespread coverage will be in 2024. While Medicare drug plans can add new drugs to their formularies during the year to reflect new approvals and expanded indications, plans are not required to cover every new drug that comes to market. Part D plans are required to cover at least two drugs in each category or class and all or substantially all drugs in six protected classes . However, facing a relatively high price and potentially large patient population for Wegovy, many Part D plans might be reluctant to expand coverage now, since they can’t adjust their premiums mid-year to account for higher costs associated with use of this drug. So, broader coverage in 2025 could be more likely.

How might expanded coverage of Wegovy affect Medicare spending?

The impact on Medicare spending associated with expanded coverage of Wegovy will depend in part on how many Part D plans add coverage for it and the extent to which plans apply restrictions on use like prior authorization; how many people who qualify to take the drug use it; and negotiated prices paid by plans. For example, if plans receive a 50% rebate on the list price of $1,300 per month (or $15,600 per year), that could mean annual net costs per person around $7,800. If 10% of the target population (an estimated 360,000 people) uses Wegovy for a full year, that would amount to additional net Medicare Part D spending of $2.8 billion for one year for this one drug alone.

It’s possible that Medicare could select semaglutide for drug price negotiation as early as 2025, based on the earliest FDA approval of Ozempic in late 2017 . For small-molecule drugs like semaglutide, at least seven years must have passed from its FDA approval date to be eligible for selection, and for drugs with multiple FDA approvals, CMS will use the earliest approval date to make this determination. If semaglutide is selected for negotiation next year, a negotiated price would be available beginning in 2027. This could help to lower Medicare and out-of-pocket spending on semaglutide products, including Wegovy as well as Ozempic and Rybelsus, the oral formulation approved for type 2 diabetes. As of 2022, gross Medicare spending on Ozempic alone placed it sixth among the 10 top-selling drugs in Medicare Part D, with annual gross spending of $4.6 billion, based on KFF analysis . This estimate does not include rebates, which Medicare’s actuaries estimated to be  31.5% overall in 2022  but could be as high as  69%  for Ozempic, according to one estimate.

What does this mean for Medicare coverage of anti-obesity drugs?

For now, use of GLP-1s specifically for obesity continues to be excluded from Medicare coverage by law. But the FDA’s decision signals a turning point for broader Medicare coverage of GLP-1s since Wegovy can now be used to reduce the risk of heart attack and stroke by people with cardiovascular disease and obesity or overweight, and not only as an anti-obesity drug. And more pathways to Medicare coverage could open up if these drugs gain FDA approval for other uses . For example, Eli Lilly has just reported clinical trial results showing the benefits of its GLP-1, Zepbound (tirzepatide), in reducing the occurrence of sleep apnea events among people with obesity or overweight. Lilly reportedly plans to seek FDA approval for this use and if approved, the drug would be the first pharmaceutical treatment on the market for sleep apnea.

If more Medicare beneficiaries with obesity or overweight gain access to GLP-1s based on other approved uses for these medications, that could reduce the cost of proposed legislation to lift the statutory prohibition on Medicare coverage of anti-obesity drugs. This is because the Congressional Budget Office (CBO), Congress’s official scorekeeper for proposed legislation, would incorporate the cost of coverage for these other uses into its baseline estimates for Medicare spending, which means that the incremental cost of changing the law to allow Medicare coverage for anti-obesity drugs would be lower than it would be without FDA’s approval of these drugs for other uses. Ultimately how widely Medicare Part D coverage of GLP-1s expands could have far-reaching effects on people with obesity and on Medicare spending.

• Medicare Part D
• Chronic Diseases
• Heart Disease
• Medicare Advantage

news release

• An Estimated 1 in 4 Medicare Beneficiaries With Obesity or Overweight Could Be Eligible for Medicare Coverage of Wegovy, an Anti-Obesity Drug, to Reduce Heart Risk

Also of Interest

• An Overview of the Medicare Part D Prescription Drug Benefit
• FAQs about the Inflation Reduction Act’s Medicare Drug Price Negotiation Program
• What Could New Anti-Obesity Drugs Mean for Medicare?
• Medicare Spending on Ozempic and Other GLP-1s Is Skyrocketing