1. 6/22/2016 Tom Gilchrist (tomg@halcyon.com) Cost and Impact of Errors/Defects Errors are introduced in all activities. The longer errors go undetected and unresolved, the more they cost to fix. Rework is inconsistent with quality objectives.

2. 6/22/2016 Tom Gilchrist (tomg@halcyon.com) Typical Lifecycle Defect Detection, Fix, and Removal Costs From SSQ Debate 2, 1991, M. Fagan

3. 6/22/2016 Tom Gilchrist (tomg@halcyon.com) Inspection Vs. Testing Dynamic Vs. Static Testing Peer Reviews can be done before code can be tested. Testing evaluates product while performing function in target environment. Not mutually exclusive

4. 6/22/2016 Tom Gilchrist (tomg@halcyon.com) Low Quality in Software Unneeded Complexity Rework -Wrong -Unclear -Missing -Extra

5. 6/22/2016 Tom Gilchrist (tomg@halcyon.com) The Quality Lever Requirements Design Coding Development Testing Acceptance Testing Improve Product Production 40-100X 30-70X 15-40X 10X 3-6X 1X Data from Boehm: Software Engineering Economics, 1981

6. 6/22/2016 Tom Gilchrist (tomg@halcyon.com) Error/Defect Classification Number of Errors MinorMajor"Show Stoppers" Find and remove as many Major and Show Stopper errors as early as possible. Error Severity

7. 6/22/2016 Tom Gilchrist (tomg@halcyon.com) Terminology Major Error An issue or defect which will probably have significantly increased costs to find and fix later in the development process or operational stages. Could conceivably make the product being produced unusable for it's intended purpose. Minor Error An issue or defect that is not major. The costs of fixing later is not significantly higher than fixing now.