Summary

Specify measures to address measurement objectives.

Description

Measurement objectives are refined into precise, quantifiable measures.

Measurement of project and organizational work can typically be traced to one or more measurement information categories. These categories include the following: schedule and progress, effort and cost, size and stability, and quality.

Measures can be either base or derived. Data for base measures are obtained by direct measurement. Data for derived measures come from other data, typically by combining two or more base measures.

 

Examples of commonly used base measures include the following:
  • Estimates and actual measures of work product size (e.g., number of pages)
  • Estimates and actual measures of effort and cost (e.g., number of person hours)
  • Quality measures (e.g., number of defects by severity)
  • Information security measures (e.g., number of system vulnerabilities identified)
  • Customer satisfaction survey scores


 

Examples of commonly used derived measures include the following:
  • Earned value
  • Schedule performance index
  • Defect density
  • Peer review coverage
  • Test or verification coverage
  • Reliability measures (e.g., mean time to failure)
  • Quality measures (e.g., number of defects by severity/total number of defects)
  • Information security measures (e.g., percentage of system vulnerabilities mitigated)
  • Customer satisfaction trends


Derived measures typically are expressed as ratios, composite indices, or other aggregate summary measures. They are often more quantitatively reliable and meaningfully interpretable than the base measures used to generate them.

There are direct relationships among information needs, measurement objectives, measurement categories, base measures, and derived measures. This direct relationship is depicted using some common examples in Table MA.1.

Table MA.1: Example Measurement Relationships

Example Project, Organizational, or Business Objectives Information Need Measurement Objective Measurement Information Categories Example Base Measures Example Derived Measures
Shorten time to delivery Be first to market the product What is the estimated delivery time? Provide insight into schedule fluctuations and progress Schedule and progress Estimated and actual start and end dates by task
Increase market share by reducing costs of products and services How accurate are the size and cost estimates? Provide insight into actual size and costs compared to plan Size and effort Estimated and actual effort and size Productivity
Effort and cost Estimated and actual cost Cost performance
Cost variance
Deliver specified functionality Has scope or project size grown? Provide insight into actual size compared to plan, identify unplanned growth Size and stability Requirements count Requirements volatility
Size estimation accuracy
Function point count Estimated vs. actual function points
Lines of code count Amount of new, modified, and reused code
Reduce defects in products delivered to the customer by 10% without affecting cost Where are defects being inserted and detected prior to delivery? Evaluate the effectiveness of defect detection throughout the product lifecycle Quality Number of defects inserted and detected by lifecycle phase
Product size		 Defect containment by lifecycle phase
Defect density
What is the cost of rework? Determine the cost of correcting defects Cost Number of defects inserted and detected by lifecycle phase
Effort hours to correct defects
Labor rates		 Rework costs
Reduce information system vulnerabilities What is the magnitude of open vulnerabilities? Evaluate the effectiveness of mitigating system vulnerabilities Information Assurance Number of system vulnerabilities identified and number of system vulnerabilities mitigated Percentage of system vulnerabilities mitigated


Example Work Products



  1. Specifications of base and derived measures


Subpractices



1. Identify candidate measures based on documented measurement objectives.

Measurement objectives are refined into measures. Identified candidate measures are categorized and specified by name and unit of measure.



2. Maintain traceability of measures to measurement objectives.

Interdependencies among candidate measures are identified to enable later data validation and candidate analyses in support of measurement objectives.



3. Identify existing measures that already address measurement objectives.

Specifications for measures may already exist, perhaps established for other purposes earlier or elsewhere in the organization.



4. Specify operational definitions for measures.

Operational definitions are stated in precise and unambiguous terms. They address two important criteria:

  • Communication: What has been measured, how was it measured, what are the units of measure, and what has been included or excluded?
  • Repeatability: Can the measurement be repeated, given the same definition, to get the same results?



5. Prioritize, review, and update measures.

Proposed specifications of measures are reviewed for their appropriateness with potential end users and other relevant stakeholders. Priorities are set or changed, and specifications of measures are updated as necessary.