Table of Contents
Metrics PLAN
- Measure – quantitative indication of extent, amount, dimension, capacity, or size of some attribute of a product or process. E.g. Number of errors
- Metric – quantitative measure of degree to which a system, component or process possesses a given attribute. “A handle or guess about a given attribute.” E.g. Number of errors found per person hours expended
Why Measure Software ?
- Determine the quality of the current product or process
- Predict qualities of a product/process
- Improve quality of a product/process
Motivation for Metrics
- Estimate the cost & schedule of future projects
- Evaluate the productivity impacts of new tools and techniques
- Establish productivity trends over time
- Improve software quality
- Forecast future staffing needs
- Anticipate and reduce future maintenance needs
Example Metrics
- Defect rates
- Error rates
- Measured by:
- individual
- module
- during development
- Errors should be categorized by origin, type, cost
Metric Classification
- Products
- Explicit results of software development activities
- Deliverables, documentation, by products
- Processes
- Activities related to production of software
- Resources
- Inputs into the software development activities
- hardware, knowledge, people
Product vs. Process
- Process Metrics
- Insights of process paradigm, software engineering tasks, work product, or milestones
- Lead to long term process improvement
- Product Metrics
- Assesses the state of the project
- Track potential risks
- Uncover problem areas
- Adjust workflow or tasks
- Evaluate teams ability to control quality
Types of Measures
- Direct Measures (internal attributes)
- Cost, effort, LOC, speed, memory
- Indirect Measures (external attributes)
- Functionality, quality, complexity, efficiency, reliability, maintainability
Size-Oriented Metrics
Size of the software produced
- LOC – Lines Of Code
- KLOC – 1000 Lines Of Code
- SLOC – Statement Lines of Code (ignore whitespace)
Typical Measures:
–Errors/KLOC, Defects/KLOC, Cost/LOC, Documentation Pages/KLOC
LOC Metrics
- Easy to use
- Easy to compute
- Language & programmer dependent
Complexity Metrics
- LOC – a function of complexity
- Language and programmer dependent
- Halstead’s Software Science (entropy measures)
- n1 – number of distinct operators
- n2 – number of distinct operands
- N1 – total number of operators
- N2 – total number of operands
Measures of Software Quality
- Correctness – degree to which a program operates according to specification
- Defects/KLOC
- Defect is a verified lack of conformance to requirements
- Failures/hours of operation
- Maintainability – degree to which a program is open to change
- Mean time to change
- Change request to new version (Analyze, design etc)
- Cost to correct
- Integrity – degree to which a program is resistant to outside attack
- Fault tolerance, security & threats
- Usability – easiness to use
- Training time, skill level necessary to use, Increase in productivity, subjective questionnaire or controlled experiment
Metric tools
- Mc Cabe & Associates ( founded by Tom McCabe, Sr.)
- The Visual Quality ToolSet
- The Visual Testing ToolSet
- The Visual Reengineering ToolSet
- Metrics calculated
- McCabe Cyclomatic Complexity
- McCabe Essential Complexity
- Module Design Complexity
- Integration Complexity
- Lines of Code
- Halstead
Project Metrics are means to measure/track process, performance and achievements based on project data captured over the period of project life cycle.
Quality Assurance Metrics measure process/performance for a project based on QA Activities done for project
- Metrics are driven by Main Process and Sub Process Goals for a project
Key Metrics for DW Testing Projects :
Test Planning Metrics
- DW Schedule Deviation
- DW Effort deviation
Test Case Design/Development Metrics
- DW Test Coverage
- DW Requirements Coverage
Test Execution Metrics
- DW Test Case Efficiency
- DW Defect Detection Rate
- DW Defect Rejection Ratio
- DW Defect Slippage Ratio
