Lecture Software process improvement: Lesson 43A provide students with knowledge about: process metrics; process quality metrics; defect density; defect arrival rate; test effectiveness; defects by phase; defect removal effectiveness;... Please refer to the detailed content of the lecture!
Process Metrics Lecture # 43A Process Quality Metrics Process Metrics • Process metrics are those that can be used for improving the software development and maintenance processes • Examples include the effectiveness of defect removal during development, the pattern of testing defect arrival, and the response time of the fix process • Compared to endproduct quality metrics, process quality metrics are less formally defined, and their practices vary greatly among software developers • Some organizations pay little attention to process quality metrics, while others have wellestablished software metrics programs that cover various parameters in each phase of the development cycle Process Metrics Process Metrics • • • • • Defect density Defect arrival rate Test effectiveness Defects by phase Defect removal effectiveness Defect Density 1 • Software defect density never follows the uniform distribution. It is an indication of defect injection in code or other software products • If a piece of code or a product has higher testing defects, either it is due to more effective testing or it is because of higher latent defects in the code • It is also possible that the more defects found during testing, the more defects will be found later Defect Density Defect Density • Defects per KLOC (or other denominator) 10 Backlog Management Index 2 • If the result is greater than 1, your team is gaining ground; otherwise it is losing • When measurements are taken at regular intervals and plotted, a trend can be observed indicating the rate at which the backlog is growing or shrinking 43 Fix Response Time 44 Fix Response Time • The fix response time metric is determined by calculating the average time it takes your team to fix a defect 45 Fix Response Time 1 • It can be measured several different ways • In some cases, it is the elapsed time between the discovery of the defect and the development of an unverified fix • In other cases, it is the elapsed time between the discovery and the development of verified fix 46 Fix Response Time 2 • A better alternative to this metric is fix response time by severity 47 Percent Delinquent Fixes 48 Percent Delinquent Fixes 1 • A fix is delinquent if exceeds your fix response time criteria • For example, if you have established a maximum fix response time of 48 hours; then fix response times that exceed 48 hours are considered delinquent 49 Percent Delinquent Fixes 50 Percent Delinquent Fixes • To calculate the percent delinquent fixes; divide the number of delinquent fixes by the number of nondelinquent fixes and multiply by 100 • PDF = (Fd / Fn) * 100 51 Percent Delinquent Fixes 2 • This metric is also measured better by severity since the consequences of having a high delinquent fixes for severe defects is typically much greater than for less severe or minor defects 52 Defective Fixes 53 Defective Fixes • A defect for which a fix has been prepared that later turns out to be defective or worse, creates one or more additional problems, is called a defective fix • The defective fixes metric is a count of the number of such fixes 54 Defective Fixes 2 • To accurately measure the number of defective fixes, your organization must not only keep track of defects that have been closed and then reopened but must also keep track of new defects that were caused by a defect fix • This metric is also known as fix quality 55 Summary 56 References • Metrics and Models in Software Quality Engineering by Stephan H. Kan (Chapter 4.24.4) [pp.99117] 57 .. .Process? ?Quality Metrics Process? ?Metrics • Process? ?metrics are those that can be used for improving the? ?software? ?development and maintenance processes • Examples include the effectiveness of ... Some organizations pay little attention to process? ?quality metrics, while others have wellestablished? ?software? ?metrics programs that cover various parameters in each phase of the development cycle Process? ?Metrics Process? ?Metrics... response time of the fix? ?process • Compared to endproduct quality metrics, process? ?quality metrics are less formally defined, and their practices vary greatly among? ?software? ?developers • Some organizations pay little attention to