Understanding Assurance Cases:
An Educational Series in Five Parts

version 2.0 (2020-07-15)
(next modification expected in 2021)

C. Michael Holloway


Module 1: Foundation (PDF)

Concentrates on the key concepts, phrases, notations, and characteristics that define assurance cases.

A person completing Foundation should be able to

  • Provide a good definition of ‘assurance case’
  • Explain the key concepts of assurance cases and recognize various terms for those concepts
  • Identify some existing notations for expressing assurance cases
  • Enumerate characteristics that an assurance case should have

Module 2: Application (PDF)

Concentrates on the history, current uses, and potential benefits and problems of assurance cases.

A person completing Application should be able to

  • Cite selected past events relevant to the development of the assurance case approach
  • List uses of assurance cases in several domains
  • Discuss possible lessons learned from past uses
  • Explain potential benefits and problems associated with assurance cases

Module 3: Evaluation (PDF)

Concentrates on the philosophy and methods for evaluating whether a particular assurance case is sufficient for its purpose.

A person completing Evaluation should be able to

  • Identify positive properties that an assurance case should have
  • Identify negative properties that an assurance case should not have
  • Enumerate steps for evaluating an assurance case
  • Suggest potential corrections for selected deficiencies

Module 4: Creation (PDF)

Concentrates on methods for creating assurance cases.

A person completing Creation should be able to

  • Enumerate steps for creating a new assurance case
  • Explain essential questions that must be answered while developing a case
  • Identify common mistakes made in assurance case creation
  • Create a simple assurance case

Module 5: Speculation (PDF)

Concentrates on the possible ways assurance cases may fit into current environments, current research in the field, and how to learn more about assurance cases.

A person completing Speculation should be able to

  • Compare and contrast an assurance case approach with other approaches
  • Discuss how an assurance case approach could fit into a regulatory environment
  • List current areas of assurance case research
  • Locate references for further study

Single PDF containing everything

If you are interested in this material, you may well be also interested in the following two recent (2020) documents: A Primer on Argument (Overarching Properties Edition) and A Friendly Argument Notation (FAN)

This material was originally created in 2015-16, as part of the Explicate ’78 project. The project was supported in substantial part by the Assurance Case Applicability to Digital Systems task under the reimbursable interagency agreement with the Federal Aviation Administration for Design, Verification, and Validation of Advanced Digital Airborne Systems Technology (IAI-1073 Annex 2 for NASA; DTFACT-10-X0008, Modification 0004 for the FAA). The original presentations were delivered to a selected group of FAA civil servants and NASA Langley personnel. The audio was recorded and partial transcripts (containing only the words spoken by the presenter, Mr. Holloway) produced. The intent from the beginning was to collect the material into a form that could be made available publicly. The text adheres closely to the original transcript, except where changes have been made to the original presentation since it was first given, as part of work for for NASA IA-303333/FAA IA NO 692M15-19-T-00029 Annex 1/TO 1.