University of Southern California Center for Systems and Software Engineering Software Metrics and Measurements Supannika Koolmanojwong CS577 1

University of Southern California Center for Systems and Software Engineering Outline General Concepts about Metrics Example of Metrics Agile Metrics Metrics from Empirical Data 2

University of Southern California Center for Systems and Software Engineering Objectives of software measurement “You can not control what you cannot measure.” – Tom DeMarco “Not everything that counts can be counted. Not everything that is counted counts.” – Albert Einstein 3

University of Southern California Center for Systems and Software Engineering Software Metrics Numerical data related to software development Strongly support software project management activities Can be directly observable quantities or can be derived from one 4

University of Southern California Center for Systems and Software Engineering A simplified measurement information model 5 Ref: Ebert and Dumke 2007 Decisions / Actions Measurements ProcessWork Products Information products Information needs Attributes Results Information Needs, Objectives, Control

University of Southern California Center for Systems and Software Engineering How the software measurements are used? Understand and communicate Specify and achieve objectives Identify and resolve problems Decide and Improve 6

University of Southern California Center for Systems and Software Engineering Measurement Standard 7 ISO/IEC Software Life Cycle Processes ISO/IEC System Life Cycle processes SWEBOK Software Engineering Body of Knowledge PMBOK Project Management Body of Knowledge CMMI Capability Maturity Model Integration ISO Software Process Capability Determination ISO 9001 Quality Management System ISO/IEC 9126 Software Product Quality TL 9000, AS 9100, etc. Objectives adaptations How to do How to do better ISO/IEC 15939:2002 Software Measurement Process How to measure what you are doing

University of Southern California Center for Systems and Software Engineering Ground rules for a Metrics Metrics must be –Understandable to be useful –Economical –Field tested –Highly leveraged –Timely –Must give proper incentives for process improvement –Evenly spaced throughout all phases of development –Useful at multiple levels 8

University of Southern California Center for Systems and Software Engineering Measurements for Senior Management Easy and reliable visibility of business performance Forecasts and indicators where action is needed Drill-down into underlying information and commitments Flexible resource refocus 9

University of Southern California Center for Systems and Software Engineering Measurements for Project Management Immediate project reviews Status and forecasts for quality, schedule, and budget Follow-up action points Report based on consistent raw data 10

University of Southern California Center for Systems and Software Engineering Project management supporting metrics 1.Planning - Metrics serve as a basis of cost estimating, training planning, resource planning, scheduling, and budgeting. 2.Organizing - Size and schedule metrics influence a project's organization. 3.Controlling - Metrics are used to status and track software development activities for compliance to plans. 4.Improving - Metrics are used as a tool for process improvement and to identify where improvement efforts should be concentrated and measure the effects of process improvement efforts. 11

University of Southern California Center for Systems and Software Engineering Measurements for Engineers Immediate access to team planning and progress Get visibility into own performance and how it can be improved Indicators that show weak spots in deliverables Focus energy on software development 12

University of Southern California Center for Systems and Software Engineering What do you want to measure? Processes –Software-related activities Products –Artifacts, deliverables, documents Resources –The items which are inputs to the process 13

University of Southern California Center for Systems and Software Engineering Components of software measurements 14

University of Southern California Center for Systems and Software Engineering Example of Metrics Progress / Effort / Cost Indicator Earned value management Requirements / Code Churn Defect-related metrics Test-related metrics 15

University of Southern California Center for Systems and Software Engineering Progress Indicator 16

University of Southern California Center for Systems and Software Engineering Effort Indicator 17

University of Southern California Center for Systems and Software Engineering Cost Indicator 18

University of Southern California Center for Systems and Software Engineering Earned value management Planned Value (PV) or Budgeted Cost of Work Scheduled (BCWS) Earned Value (EV) or Budgeted Cost of Work Performed (BCWP) 19

University of Southern California Center for Systems and Software Engineering Burndown Chart 20

University of Southern California Center for Systems and Software Engineering Requirements Churn/ Requirements Creep/ Requirements Volatility number of changes to system requirements in each phase/week/increment 21

University of Southern California Center for Systems and Software Engineering Code Churn Software change history Large / recent changes Total added, modified and deleted LOC Number of times that a binary was edited Number of consecutive edits 22

University of Southern California Center for Systems and Software Engineering Code Complexity Gathered from code itself Multiple complexity values Cyclomatic complexity Fan-In / Fan-Out of functions Lines of Code Weighted methods per class Depth of Inheritance Coupling between objects Number of subclasses Total global variables 23

University of Southern California Center for Systems and Software Engineering Code coverage Degree to which the source code is tested Statement coverage –Has each node in the program been executed? Branch coverage –Has each control structure been evaluated both to true and false? 24

University of Southern California Center for Systems and Software Engineering Code Coverage 25

University of Southern California Center for Systems and Software Engineering Defect reporting metric Can be categorized by –Status Remaining / Resolved / Found –Defect Sources Requirements / Design / Development –Defect found Peer review / unit testing / sanity check –Time Defect arrival rate / Defect age 26

University of Southern California Center for Systems and Software Engineering Defect Status 27

University of Southern California Center for Systems and Software Engineering Defect Density 28

University of Southern California Center for Systems and Software Engineering Test Pass Coverage 29

University of Southern California Center for Systems and Software Engineering Defect Density 30

University of Southern California Center for Systems and Software Engineering 31 Ref: Measuring Agility, Peter Behrens

University of Southern California Center for Systems and Software Engineering 32 Ref: Measuring Agility, Peter Behrens Velocity = Work Completed per sprint

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University of Southern California Center for Systems and Software Engineering Measurements in organizational level Empirical analysis Change from the top 34

University of Southern California Center for Systems and Software Engineering 35 Richard W. Selby, Northrop Grumman Space Technology, ICSP '09 Title: "Synthesis, Analysis, and Modeling of Large-Scale Mission-Critical Embedded Software Systems"

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University of Southern California Center for Systems and Software Engineering 37

University of Southern California Center for Systems and Software Engineering Measurements for progress vs predictions Project PhaseFor MeasurementsFor Predictions Project Management -Effort and Budget Tracking - Requirements Status -Task Status -Top 10 risks - Cost to complete - Schedule evolution Quality Management -Code Stability -Open defects -Review status and follow up -Residual defects -Reliability -Customer satisfaction Requirements Management -Analysis status -Specification progress -Requirements volatility / completeness Construction-Status of documents - Change requests -Review status -Design progress of reqm - Cost to complete -Time to complete TestTest progress (defects, coverage, efficiency, stability - Residual defects - reliability Transition, deployment -Field performance (failure, corrections) - maintenance effort -Reliability -Maintenance effort 38 Ref: Ebert and Dumke, 2007

University of Southern California Center for Systems and Software Engineering References htmlhttp://sunset.usc.edu/classes/cs577b_2001/metricsguide/metrics. html Fenton NE, Software Metrics: A Rigorous Approach, Chapman and Hall, Christof Ebert, Reiner Dumke, Software measurement: establish, extract, evaluate, execute, Springer Richard W. Selby, Northrop Grumman Space Technology, ICSP '09 Title: "Synthesis, Analysis, and Modeling of Large-Scale Mission- Critical Embedded Software Systems“ Measuring Agility, Peter Behrens 39