Assurance cases provide a structured method of explaining why a system has some desired property, e.g., that the system is safe. But there is no agreed approach for explaining what degree of confidence one should have in the conclusions of such a case. In this paper, we use the principle of eliminative induction to provide a justified basis for assessing how much confidence one should have in an assurance case argument.

In this paper, we define what exception conditions are, discuss the requirements exception handling language features must satisfy, survey and analyze existing approaches to exception handling, and propose some new language features for dealing with exceptions in an orderly and reliable way. Our objective is not solely to put forward a language proposal. It is also to analyze exception handling issues and principles in detail. The proposed language features serve to highlight exception handling issues by showing how deficiencies in current approaches could be remedied in a coherent and orderly way.

Examines the theoretical and practical role of testing in software development. The authors prove a fundamental theorem showing that properly structured tests are capable of demonstrating the absence of errors in a program. The theorem's proof hinges on our definition of test reliability and validity, but its practical utility hinges on being able to show when a test is actually reliable. The authors explain what makes tests unreliable (for example, they show by example why testing all program statements, predicates, or paths is not usually sufficient to insure test reliability), and they outline a possible approach to developing reliable tests. They also show how the analysis required to define reliable tests can help in checking a program's design and specifications as well as in preventing and detecting implementation errors.