Project Metrics

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Project Metrics
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Overview

• Motivation
• Characterize
• evaluate
• predict
• improve
• software engineering
• more difficult to quantify
• lack of consensus

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Overview cont

• Goal - indicator
• metric that provides insight
• allow early detection of potential problems
• need to be careful that metrics measure concept
  of interest
• to measure process - must use data related to
  process

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Overview cont

• Public vs. Private use of metrics
• private - only available to individual or group
• public - usually summary of private information
• metric (like any evaluation tool) - can be used
  to help promote improvement or input in personnel
  actions

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Overview cont

• Statistical software process improvement - uses
  software failure analysis to collect information
  about all errors defects
• failure analysis
• errors defects - categorized by origin
• cost to correct each error defect - recorded
• compare number of errors defects by category

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Overview cont

• compare cost of errors defects by category
• analyze results to uncover problem categories
• develop plans to modify process to reduce most
  costly errors
• project metrics
• used to modify workflow technical activities
• give ongoing assessment of product quality

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Software Measurements

• Direct measures
• measure quantity immediately
• speed, size, ...
• Indirect measures
• ilities - functionality, reliability,
  maintainability, ...
• Size-oriented metrics
• need to normalize wrt size of project
• common (but not best) approach - normalize wrt
  lines of code

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Software Measurements cont

• Function oriented metrics
• measure of functionality - used as normalization
  value calculated from other measures
• function point - related to achievement of
  specification
• domain characteristics considered
• number of user inputs
• number of user outputs

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Software Measurements cont

• number of user inquiries
• number of files
• number of external interfaces
• Complexity value - associated with each count
• many methods of averaging these values
• extended function point metrics
• function point - inadequate for engineering
  embedded systems
• feature point
• takes into account complexity of algorithms

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Software Measurements cont

• relationship between lines of code function
  points - programming language dependent

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Metrics for Software Quality

• Need technical measures - not subjective measures
• project scope - measure errors defects
• errors per function point
• errors uncovered per peer review
• errors uncovered per testing hour

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Metrics for Software Quality cont

• Points of view of quality
• product operation (using)
• product modification (modifying)
• product transition (porting)
• indicators of quality
• correctness
• performs required functions
• most common measure - KLOC

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Metrics for Software Quality cont

• Maintainability
• ease with which programs can be modified
• indirect measures used
• MTTC (mean time to change)
• spoilage - cost to modify
• integrity
• ability to withstand attacks to security
• use attributes
• threat - probability that an attack will occur
  within a specified time interval
• security - probability that an attack will be
  repelled

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Metrics for Software Quality cont

• Integrity
• usability
• characteristics
• physical intellectual skill required to learn
  system
• time required to become moderately efficient
• net increase in productivity for moderately
  efficient user
• users attitudes
• defect removal efficiency (DRE)
• E - number of errors
  before delivery
• D - number of
  errors after delivery

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Reasons for Using Metrics

• Without measurements - cannot tell whether
  improving
• meaningful goals can be established

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SEI Guidelines for Establishing a Metrics Program

• Identify business goals
• identify what want to know
• identify subgoals
• identify entities attributes related to
  subgoals
• formalize measurement goals

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SEI Guidelines for Establishing a Metrics Program
cont

• identify quantifiable questions related
  indicators
• Identify data elements to be collected
• define measures to be used
• identify actions to implement measures
• prepare plan for implementing measures