1. 9/8/99Lecture 51 CIS 4251 / CIS 5930 SOFTWARE DEVELOPMENT Fall 1999 Sept. 8, 1999 Marge Holtsinger

2. 9/8/99Lecture 52 Teams 4 Team Name 4 Team Members –Name, Year in School, Myers/Briggs Indicator, Strengths, Weaknesses 4 Team Roles & Responsibilities –Project Manager, Analyst, Design, Development, Testing, User Ed, Logistics

3. 9/8/99Lecture 53 Lecture Overview 4 Review of Previous Discussion 4 Project Metrics 4 Project Estimates

4. 9/8/99Lecture 54 What Are Project Metrics? Measurement Based Techniques Processes, Products & Services Applied To Supply To Improve Engineering & Management Information

5. 9/8/99Lecture 55 Definitions 4 Measure - provides a quantitative indication of the extent, amount, dimensions, capacity, or size of some attribute of a product or process. 4 Measurement - act of determining a measure. 4 Metric - “A quantitative measure of the degree to which a system, component, or process possesses a given attribute.” 4 Indicator - metric or combination of metrics that provide insight into the software process, a software project, or the product itself.

6. 9/8/99Lecture 56 Software Metrics Dos and Don’t 4 Don’t measure individuals 4 Never use metrics as a ‘stick’ 4 Don’t ignore the data 4 Never use only one metric 4 Select metrics based on objectives 4 Provide feedback 4 Obtain “buy-in”

7. 9/8/99Lecture 57 Fishbone Diagram

8. 9/8/99Lecture 58 Why Collect Metrics? 4 Used to minimize the development schedule 4 Used to assess product quality on an ongoing basis

9. 9/8/99Lecture 59 Size-Oriented Metrics 4 Often based on LOC –Errors per KLOC –Defects per KLOC –$ per LOC –Pages of documentation per KLOC 4 Not universally accepted because of LOC determination

10. 9/8/99Lecture 510 Function-Oriented Metrics FP=count total x [.65 +.01 x  F(i)] where i=1-14

11. 9/8/99Lecture 511 Software Productivity Influences 4 People factors 4 Problem factors 4 Process factors 4 Product factors 4 Resource factors

12. 9/8/99Lecture 512 Measuring Quality 4 Correctness 4 Maintainability 4 Integrity 4 Usability

13. 9/8/99Lecture 513 Defect Removal Efficiency 4 DRE = E/(E+D) where –E=number of errors found before delivery of the software to the end user –D=number of defects found after delivery 4 Ideal value is 1

14. 9/8/99Lecture 514 7 Steps to Designing a Software Metric 4 Objective Statement 4 Clear Definitions 4 Define the Model 4 Establishing Counting Criteria 4 Decide What’s Good 4 Metrics Reporting 4 Additional Qualifiers

15. 9/8/99Lecture 515 Software Project Planning 4 Estimating 4 Features and Priorities 4 Risk Assessment 4 Resources 4 Milestones and Deliverables

16. 9/8/99Lecture 516 Software Project Estimation 4 Not an exact science 4 More accurate if delay estimation until late in the project 4 Base estimates on similar projects 4 Decomposition techniques to estimate effort & cost 4 Empirical models to estimate effort & cost

17. 9/8/99Lecture 517 ? That Contribute to Uncertainty 4 Will customer want Feature X? 4 Will customer want the cheap or expensive version of Feature X? 4 If you implement the cheap version of Feature X, will the customer later want the expensive version? 4 How will feature X be designed?

18. 9/8/99Lecture 518 Software Sizing 4 “Fuzzy-logic” sizing 4 Function point sizing 4 Standard component sizing 4 Change sizing

19. 9/8/99Lecture 519 Estimate Multipliers by Project Phase

20. 9/8/99Lecture 520 Guidelines for Making Size Estimates 4 Avoid off-the-cuff estimates 4 Allow time for the estimate, and plan it 4 Use data from previous projects 4 Use developer-based estimates 4 Estimate by walkthrough 4 Estimate by categories 4 Estimate at low level of detail

21. 9/8/99Lecture 521 Guidelines... 4 Don’t omit common tasks 4 Use software estimation tools 4 Use several different estimation techniques, & compare results 4 Change estimation practices as the project progresses

22. 9/8/99Lecture 522 Estimate Presentation Styles 4 Plus-or-minus qualifiers 4 Risk quantification 4 Case-based estimation 4 Confidence-factor estimate

23. 9/8/99Lecture 523 LOC Based Estimation 4 Major functions are identified 4 Range of values for LOC for each function are estimated 4 Must have historical data to determine productivity

24. 9/8/99Lecture 524 FP-Based Estimation 4 Based on information domain values –Number of inputs –Number of outputs –Number of inquiries –Number of files –Number of external interfaces 4 Complexity factors are then determined

25. 9/8/99Lecture 525 Process-Based Estimation 4 Estimate effort required for each software process / phase of the project –Vision/Scope –Project plan –Analysis –Design –Development

26. 9/8/99Lecture 526 Effort and Schedule Estimate 4 Effort estimate helps determine resources 4 Schedule estimate is computed using the following equation: –Schedule in months=3*man-months^1/3 –Can substitute 4 or 2.5 for the factor 3

27. 9/8/99Lecture 527 Estimation Facts of Life 4 There is a shortest possible schedule, and you cannot beat it. 4 Costs increase rapidly when you shorten the schedule below nominal –Schedule compression factor –Compressed schedule effort

28. 9/8/99Lecture 528 Recalibrating an Estimate 4 What if you missed the first milestone by 1 week? Should you –Assume you can make up the lost week later in the schedule –Add the week to the total schedule –Multiply the whole schedule by the magnitude of the slip, ie 25% if 1 week late for 4 week milestone

29. 9/8/99Lecture 529 What Causes Poor Estimates 4 Scope of project not understood 4 Productivity data is incorrect

30. 9/8/99Lecture 530 Empirical Estimation Models 4 Based on historical data on LOC and FP 4 Derived using regression analysis on data collected from past software projects –E=A+B*(ev) c A, B, & C are derived constants, E is the effort in person months, and ev is the estimation variable

31. 9/8/99Lecture 531 Risks 4 Definition –Possibility of suffering lose or harm –Factor, element, or course involving uncertain danger 4 Characteristics –Associated with lose –Includes uncertainty of occurrence, impact, and outcome –Has aspects of gain and loss

32. 9/8/99Lecture 532 Risk Management Principles 4 Assess risks continuously 4 Includes all key people 4 Are generally known but communicated 4 Must be clearly stated 4 Important risks are dealt with first

33. 9/8/99Lecture 533 Risk Identification 4 Product size 4 Business impact 4 Customer characteristics 4 Process definition 4 Development environment 4 Technology 4 Staff size and experience

34. 9/8/99Lecture 534 Risks Consequences 4 Cost overruns 4 Schedule slips 4 Inadequate functionality 4 Canceled projects 4 Sudden personal changes 4 Customer dissatisfaction 4 Loss of company image 4 Demoralized staff 4 Poor product performance 4 Legal proceedings

35. 9/8/99Lecture 535 Approaches to Risk Management 4 Reactive –Mitigation of symptoms; Fix on failure –Crisis management 4 Transitional –Preventive 4 Proactive –Elimination of root causes; Anticipation of risk –Change management