Accident investigation and risk assessment have for decades focused on the human factor, most notably in the form of 'human error'. Countless books and papers have been written about how to identify, classify, eliminate, prevent and compensate for 'human error'. This preoccupation with failure is near universal and can be found in all fields of application. One consequence of this has been a bias towards the study of performance failures, leading to a neglect of normal or 'error-free' performance. The common, unspoken assumption is that failures and successes have different origins and that there therefore is little to be gained from studying the latter. Erik Hollnagel argues strongly that this assumption is incorrect and that it is impossible to attain safety by eliminating risks and failures. Instead it is better to study why things go right, and to find ways to support and amplify that. The aim of this book is to present a single, simple but powerful principle for human performance that can be used to understand both positive and negative outcomes. The ETTO Principle reflects the common trait that people in their work naturally adjust what they do to match the conditions - to what has happened, to what happens, and to what may happen. It proposes that it is normal for people in work situations to adjust their performance by means of an efficiency-thoroughness trade-off (ETTO) - usually by sacrificing thoroughness for efficiency. The trade-off can be due to a lack of time, lack of resources, work and company pressures, lack of information, etc. The ability of people mutually to adjust their performance is the reason why things go right. Yet in some cases the adjustments may combine in an unforeseen way and lead to adverse outcomes. These outcomes are nevertheless due to the very same processes that produce successes, rather than to errors and malfunctions. The ETTO Principle obviates the need for specialised theories and models of failure and 'human error' and offers instead a viable basis for more effective and just approaches to both reactive and proactive safety management.

Testing is a key component of agile development. The widespread adoption of agile methods has brought the need for effective testing into the limelight, and agile projects have transformed the role of testers. Much of a tester's function, however, remains largely misunderstood. What is the true role of a tester? Do agile teams actually need members with QA backgrounds? What does it really mean to be an "agile tester?" Two of the industry's most experienced agile testing practitioners and consultants, Lisa Crispin and Janet Gregory, have teamed up to bring you the definitive answers to these questions and many others. In Agile Testing, Crispin and Gregory define agile testing and illustrate the tester's role with examples from real agile teams. They teach you how to use the agile testing quadrants to identify what testing is needed, who should do it, and what tools might help. The book chronicles an agile software development iteration from the viewpoint of a tester and explains the seven key success factors of agile testing. Readers will come away from this book understanding * How to get testers engaged in agile development * Where testers and QA managers fit on an agile team * What to look for when hiring an agile tester * How to transition from a traditional cycle to agile development * How to complete testing activities in short iterations * How to use tests to successfully guide development * How to overcome barriers to test automationThis book is a must for agile testers, agile teams, their managers, and their customers.