chapter 1 Introduction -- chapter 2 Variations in Software Activities by Type of Software -- chapter 3 Variations in Software Development Activities by Type of Software -- chapter 4 Variations in Occupation Groups, Staff Size, Team Experience -- chapter 5 Variations due to Inaccurate Software Metrics That Distort Reality -- chapter 6 Variations in Measuring Agile and CMMI Development -- chapter 7 Variations among 60 Development Methodologies -- chapter 8 Variations in Software Programming Languages -- chapter 9 Variations in Software Reuse from 0% to 90% -- chapter 10 Variations due to Project, Phase, and Activity Measurements -- chapter 11 Variations in Burden Rates or Overhead Costs -- chapter 12 Variations in Costs by Industry -- chapter 13 Variations in Costs by Occupation Group -- chapter 14 Variations in Work Habits and Unpaid Overtime -- chapter 15 Variations in Functional and Nonfunctional Requirements -- chapter 16 Variations in Software Quality Results -- chapter 17 Variations in Pattern-Based Early Sizing -- chapter 18 Gaps and Errors in When Projects Start. When Do They End? -- chapter 19 Gaps and Errors in Measuring Software Quality -- chapter 20 Gaps and Errors due to Multiple Metrics without Conversion Rules -- chapter 21 Gaps and Errors in Tools, Methodologies, Languages