A New Approach to Assessment of Confidence in Assurance Cases

Xingyu Zhao*, Dajian Zhang, Minyan Lu, Fuping Zeng

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

16 Citations (Scopus)


An assurance case is a body of evidence organized into an argument demonstrating that some claims about a system hold. It is generally developed to support claims in areas such as safety, reliability, maintainability, human factors, security etc. Practically, both argument and evidence are imperfect, resulting in that we can hardly say the claim is one hundred percent true. So when we do decision-making against assurance cases, we need to know how much confidence we hold in the claims. And the quantitative confidence would provide benefits over the qualitative one. In this paper, an approach is proposed to assess the confidence in assurance cases (mainly arguments) quantitatively. First we convert Argument Metamodel based (ARM-based) cases into a set of Toulmin model instances; then we use Hitchcock's evaluative criteria for solo-verb-reasoning to analyze and quantify the Toulmin model instances into Bayesian Belief Network (BBN); running the Bayesian Belief Network, we get quantified confidence from each claim of the assurance case. Finally, we illustrate our approach by using a simplified fragment from safety cases and discuss several future work.

Original languageEnglish
Title of host publicationComputer Safety, Reliability, and Security
EditorsFrank Ortmeier, Peter Daniel
Number of pages13
ISBN (Electronic)9783642336751
ISBN (Print)9783642336744
Publication statusPublished - 2012
Event31st International Conference on Computer Safety, Reliability and Security 2012 - Magdeburg, Germany
Duration: 25 Sept 201228 Sept 2012

Publication series

NameLecture Notes in Computer Science
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference31st International Conference on Computer Safety, Reliability and Security 2012
Abbreviated titleSAFECOMP 2012


  • Assurance case
  • Bayesian Belief Network
  • informal logic
  • quantified confidence
  • Toulmin model

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


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