In a software project, the software is designed to build a source code, but from time to time or step by step, checking source code is required.
Check whether the work is going in the right direction or the process followed is correct or not. Metrics conducts this checking.
Metrics are tools used to measure and set the standard of quality of the software. Metrics are numbers and pointers which help user to understand various attributes of product, process, and project (three Ps).
- Product complexity, size, and quality, etc.
- Improve process quality and speed of development.
- Project costs, number of resources, and timeline, among others.
When software shows these qualities, it is considered quality software.
- Software must be bug or defect-free.
- It is delivered on time.
- Prepared, tested, and maintained within a budget.
- Fulfill user requirements or expectations.
Critical points of software quality regarding customer care:
- Good design of software includes software looks and style
- Good functionality of software reveals its working power.
- Reliability is the fulfilment of customer requirements and its acceptable level of breakdowns or failures.
- Consistency shows that software is continuously working on customers' systems.
- Durability reflects the long-lasting working of the software.
- Software must remain good after-sales service.
- Software is worth customer money.
Importance of software quality metrics
- Software quality metrics act as a health indicator of the process, project, and product.
- Metrics accurate data will help in developing a strategy for the proper working in process and project.
- It also highlights the critical areas that require particular focus and attention.
- Accurate metric data will help in making strategic decisions.
- Check the driving performance of software and many others.
Various metrics used to measure the product, project, and process quality of software:
- Defect Removal Efficiency (DRE)
Defect removal efficiency quality metrics are an essential metric to measure the effectiveness of the testing team. It tells about the number of defect removal rates by the testing team.
- Defect density
Several bugs and defects found in the first measure of the quality of any product define the defect density.
More defects in software = Poor quality of software development
Management tries hard to improve the number of defects to improve development and does a root cause analysis (RCA) to answer why product quality is lacking?
The software development team intensely focuses on removing defects to improve software quality by using defect density quality metrics.
- Meantime between failures (MTBF)
MTBF = Average time between two failures
It calculates the mean period between the occurrence of the first failure and second failure.
Definition of failure is based on the module and business expectations because every software has its requirements.
No development team can produce bug-free software; therefore, the mean time failure must be as high as possible.
In software, failure can be of any type like for online website and application, disconnection with the database can be a failure.
Error in source code, implementation error, software compatibility can be counted as a failure of software.
So, the testing team must keep the MTBF high to improve the quality of the software.
- Cycle time
There is a minute difference between cycle time and lead time.
Lead time = this time is measured per user story (per iteration)
Cycle time = Here, per-task time is measured.
Total time taken in implementing a particular task is termed ad cycle time.
For example, the time taken to create a database is cycle time.
The time taken to have a complete database ready (including creation, insertion and deletion, modification of data in database) would be the lead time.
- Team velocity
During a single time box, how many tasks are performed and completed by the team?
This count is defined as team velocity.
Incomplete items or tasks or backlogs are not counted in this. Only the task performed to complete iteration is included for velocity calculation. It is an essential metric based on team velocity; the management team decides the number of stories picked up for the next time- box.
- The first time pass rate
The first-time pass rate metric defines the number of test cases pass in the first run itself (number of test cases made to test the module and test cases results in zero defects).
It indicates the quality of development as this metric aligns with the agile principle of fast, dynamic, and quality delivery.
First-time pass rate < quality of software.
No defects were found in the developed code during its first time testing by the developer. Less the first time pass rate of a module, more the nest quality of the software.
- Lead time
These metric measures the lead time of the project. Lead time refers to the time taken in completing an iteration of the project from the starting of the project.
In the agile process, development takes place in different iterations, and the period required to complete iteration is called a time box.
So, lead time = time box kicks off to the completion.
- Application crash rate
ACR = How often the website of a mobile app crashes in any environment.
This metric is an indicator of the code as it measures the code and better the code the longer it is sustained without crashing.
More the application rate less the quality rate of the application or software.
- Meantime to recover (MTTR)
Time taken from the detecting period of defect to remove the defect in the system is termed as mean time to recover.
Overall, the recovery time of the defect (developers find the critical issue, fix it, and fix the production solution) in software. 24-hour MTTR > 2 days MTTR.