Software Metrics

Why do we need metrics and measures?

Measurement of software is a fundamental requirement of Software Engineering. Metrics and measures are interchangeably used in software development to monitor the product development and quality. Software metrics are the measurements of a system, product, or process used to determine the degree or units of any attribute.

The following attributes can measure the software:

• How many lines of code are there?
• How much time does it take to load inside the memory?
• How much time does it take for execution?
• What is the size of the program?
• How many bugs per line of code are there, and many other attributes are included.

Where are Software Metrics used?

Metrics are linked to management's four functions which include:

• Planning: How we are going to plan the development of the project.
• Organizing: Starting the project after organizing, like who will design and who will test.
• Controlling: While the process is ongoing, how will you control and manage the tasks.
• Improving: After completing the project, its maintenance and enhancement come under this.
   

Also read  V Model in Software Engineering

Types of Software Metrics

Here are the types of software metrics:

1. Product Metrics
2. Project Metrics
3. Process Metrics

Let’s discuss the following types of software metrics.

Product Metrics

The whole software can be considered a product, so we have some metrics we can use to measure its relevant aspects. Here are some other software metrics which we can use:
 

1. Size Oriented Metrics
   By analyzing your software production size, you can normalize quality and productivity measures. We can then develop a set of simple size-oriented metrics using LOC(Line of Code) as the normalization value.
    
2. Function Point (FP) Metrics
   An application's functionality is measured and used as a standardization value. A measure of the function is called Function Point. It cannot be directly measured; indirect measures must determine it.
    
3. Halstead's Software Metrics
   The software metrics should reflect how algorithms are implemented or expressed in different languages but not executed on a specific platform. Halstead made this observation. These metrics are therefore computed statically from the code.
    
4. Extended Function Point (EEP) Metrics
   For many embedded and engineering systems, Function Points were inadequate. There have been several extensions to the primary function point measure suggested to overcome this: 
   Feature Points: The subset of the Feature points measured by Function points (FP). These can be if the complexity of an application is relative.
   3D: A 3D function point represents three dimensions: data, function, and control.
    
5. Data Structure Metrics
   It is essentially a need for data processing to justify software development. Various data types are input to systems, programs, or modules; some data is used internally; and some information results from these systems, programs, or modules. Data Structure metrics are used to calculate the time and effort to complete the project.
    
6. Information Flow Metrics
   By looking at the amount and size of data flowing into and out of a module, we can define the strength of the module. According to this variant, the complexity of a module depends not only on the information that flows into and out of it but also on how many modules it is flowing across. 
    
7. Cyclomatic Complexity
   There is an upper bound on the number of tests that must be conducted to ensure that all the statements in the basis set have been executed at least once based on the Cyclomatic complexity, which defines the number of independent paths in the basis set of the program.
   After calculating all these metrics, you can say that you have all the quality metrics for the software product available.

Process Metrics

Some metrics help to improve the software development process. For example, there may be bugs or defects when you are developing software. Your ability to effectively and timely resolve them will determine how well the development progresses and how well the software will be maintained after being delivered to the customer.

Project Metrics

When software is in development, it is considered a project for a team and is called a product at the end of development. That's how the software is described as a project. 

The following are their characteristics:

1. Cost of developing software: A customer's budget shouldn't be exceeded by the cost of the software. Developers should take note of the increasing cost of software and come up with effective strategies to prevent it from happening. 
    
2. Schedule of Software Development: The customer should receive the software within the specified timeframe. In developing the project, it should be divided into modules, and each module should be given a limit of 2-3 days. If this is not going well and this limit is exceeded, you need to develop new strategies to complete the project on time.
    
3. Staffing Pattern: In a project, team members should be active and not take too many holidays. They should also have the right skill set needed for the project. 

Types of Measures 

1. Direct Measure: Cost, effort, length of code (LOC), speed, and memory are internal attributes that these metrics can measure.
2. Indirect Measure: It is used to measure quality, functionality, complexity, efficiency, reliability, and maintainability along with assessing external attributes.

Advantages and Disadvantages of Software Metrics

Advantages of Software Metrics

Some benefits of Software Metrics are:

• Using software quality metrics to improve software development workflow can benefit the management.
• Contribute to improving return on investment.
• Better control and visibility of the SDLC process
• Enhances the quality and quantity of production
• During this process, you will learn about various test techniques and methods.
• Detecting errors that cause problems at the beginning of the development process
• Software size and cost can be determined.
• Information about the quality and productivity of an organization can be helpful.
• Stakeholders can analyze the operation of organizations with the help of software development mattresses.

Disadvantages of Software Metrics

• Software metrics have multiple definitions and are a waste of resources. This lack of clarity follows from the inconsistency of the terms.
• Sometimes it is difficult and costly to apply software metrics.
• Based on historical data, it isn't easy to verify the validity of all software metrics, and, as a result, they cannot be confirmed.
• Assuming metrics are not standardized can be deduced from two factors: two goals and a working environment.
• Most predictive models depend on estimates of certain variables that are rarely accurate.
• For evaluating the performance of technical staff, software metrics are not helpful.

Scope of Software Metrics

The scope of Software Metrics in the Software Project Management includes:

• Data gathering
• Methods and performance evaluations
• Measures and models of quantity
• Measures and models of productivity
• A model of reliability
• Metrics of structure and complexity
• Performance
• Metrics-based management 
• Evaluation of tools and methods
• estimation of costs and effort

FAQs

1. How do you define a good metric?
   You can define it by following the features:
   → Easily computable and simple 
   → Attractiveness
   → Goal-oriented/consistent
   → Consistency in measurement units/dimensions
   → Language-independent programming
   → Provides valuable feedback
    
2. How can we measure the number of defects?
   Initially, existing bugs can significantly impact the number of bugs discovered, which in turn gives an incorrect measure of the quality of the software. It's important to measure software quality by identifying defects based on their criticality levels.
    
3. How do software quality metrics achieve their objectives?
   The Software quality Metrics achieve their objective by indicating how effective and efficient the software process is. By analyzing these metrics, the areas in which more improvements are needed can be identified. These metrics assist people in making intelligent and informed decisions.
    
4. What is the difference between software metrics and software measurement?
   Measurement is the process of determining the amounts, dimensions, capacities, and sizes of product and process attributes in a quantitative manner. On the other hand, metrics are quantitative measures that give software engineers insight into software processes, projects, and products.
    
5. Write about some characteristics of Software Metrics.
   Here are some Characteristics:
   → The required functionalities should be provided
   → Real users can use the system
   → Reliable, trustworthy, and predictable
   → Effectively performs its functions
   → Should live a long life based on the number of years
   → Assists in providing an appropriate user interface
   → Should provide complete documentation
   → The system can be easily maintained

Key Takeaways

This article is about software metrics and how they can be used in software project management Metrics are the measurement of software properties or specifications. We have seen different types of software metrics and other metrics used in Product Metrics.

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Happy Coding!