This document discusses software metrics. It defines a software metric as a standard measure of a software system or process's properties. The document then classifies metrics into product, process, and resource metrics. It describes several types of product metrics including size, complexity, Halstead's, and quality metrics. The document recommends using a GQM (Goal, Question, Metric) approach to implement an effective metrics program. It provides references for further reading.

1. Software Metrics
Swati J. Patel
M. E. (CSE)

2. Agenda
• Definition
• Need
• Classification
• Product Metrics
– Size Metrics
– Complexity Metrics
– Halstead’s Product Metrics
– Quality Metrics
• A Metrics Programme
– GQM Approach

3. Definition
A software metric is a standard of measure of a
degree to which a software system or process
possesses some property.
A Metric is a quantitative measure of the degree to
which a system, system component, or process
possesses a given attribute. Software Metrics are
used to measure the quality of the project. Simply,
Metric is a unit used for describing an attribute.
Metric is a scale for measurement.

4. Need
• Software testing is the process of identifying the flaws or
defects in the system and make sure it is compliant with
the client requirements before releasing it to the market.
• But testing can never assure 100% bug free software.
This might show the inconsistency and inefficiency of
testing process or testing methodologies followed, it
could also account the human errors in case of manual
testing or script errors in case of automated testing.
• This directly impacts the quality of the software. Hence,
in order to improve the software quality, certain
protocols and rules need to be laid down and
complement the efficiency of the software.
•

5. Classification
1
• Product Metrics
• Process Metrics
• Resource Metrics
2
• Objective Metrics
• Subjective Metrics
3
• Primitive / Direct Metrics
• Computed / Indirect Metrics

6. Product Metrics
• Size Metrics
• Complexity Metrics
• Halstead’s Product Metrics
• Quality Metrics

7. Product Metrics - Size
• LOC
• Function Points
• Bang

8. Product Metrics - Complexity
• Cyclomatic Complexity- v(G)
v(G) = e – n + 2
• Extensions to v(G)
v’(G) = [l:u]
• Knots
• Information Flow
c = [procedure length] x [(fan-in) x (fan-out)]2

9. Product Metrics - Halstead’s
Product Metrics
• Program Vocabulary
n = n1 + n2
• Program Length
N = N1 + N2
• Program Volume
V = N log2 n

10. Product Metrics - Quality Metrics
• Defect Metrics
• Reliability Metrics
• Maintainability Metrics

11. A Metrics Programme
A GQM Approach

12. References
[1] Everald E. Mills “Software Metrics”,
SEI Curriculum Module SEI-CM-12-
1.1, December 1988
[2] K.K. Aggarwal, Yogesh Singh,
“Software Engineering”, New Age
International Publishers, 3/e, 2008.