How do you apply the COSMIC method for test estimation in systems engineering?

1 What is COSMIC?

COSMIC stands for Common Software Measurement International Consortium, and it is a standard method for measuring the functional size of software systems. Functional size is the amount of functionality that a system provides to its users, based on the user requirements and the system design. COSMIC measures the functional size by counting the number of data movements between the system and its users or other systems, and categorizing them into four types: Entry, Exit, Read, and Write. Each data movement has a size of one COSMIC Function Point (CFP).

2 Why use COSMIC for test estimation?

COSMIC can be used for test estimation in systems engineering for several reasons. First, COSMIC is independent of the technology, methodology, and complexity of the system, which makes it applicable to any type of software system. Second, COSMIC is based on a clear and objective definition of functionality, which reduces the ambiguity and subjectivity of test estimation. Third, COSMIC can be applied at any stage of the system development lifecycle, from requirements analysis to implementation, which allows for early and continuous test estimation. Fourth, COSMIC can be correlated with other metrics, such as effort, duration, quality, and productivity, which enables more accurate and realistic test planning and control.

3 How to apply COSMIC for test estimation?

To apply COSMIC for test estimation in systems engineering, you need to follow four steps. First, you need to identify the functional processes of the system, which are the logical groups of data movements that deliver a specific user requirement or function. Second, you need to identify the data groups of the system, which are the sets of data attributes that are logically related and manipulated by the system. Third, you need to count the number of data movements of each type (Entry, Exit, Read, and Write) for each functional process, and assign a size of one CFP to each data movement. Fourth, you need to sum up the CFPs of all the functional processes to obtain the total functional size of the system.

4 How to use COSMIC for test estimation?

Once you have obtained the functional size of the system using COSMIC, you can use it for test estimation in various ways. For example, you can use it to estimate the test effort, by multiplying the functional size by a factor that reflects the complexity, quality, and scope of the testing activities. You can also use it to estimate the test duration, by dividing the test effort by the available test resources and adjusting for dependencies and risks. You can also use it to estimate the test coverage, by comparing the functional size with the number of test cases executed or planned. You can also use it to monitor and control the test progress, by tracking the changes in the functional size and the test metrics over time.

5 What are the benefits and limitations of COSMIC for test estimation?

COSMIC for test estimation has several benefits and limitations that you should be aware of. This standard, widely recognized method for functional size measurement enhances the credibility and comparability of test estimation. It is a simple and intuitive method that can be easily learned and applied by testers and engineers without requiring specialized tools or skills. Furthermore, it is a flexible and adaptable method that can be tailored to the specific characteristics and needs of the system and the project, without compromising its consistency and validity. On the other hand, COSMIC relies on the availability and quality of the user requirements and the system design, which may not always be clear, complete, or stable. Additionally, it does not account for the non-functional aspects of the system such as performance, security, usability, or reliability. Finally, COSMIC does not provide a definitive or precise answer for test estimation but rather a range or an approximation that needs to be validated and refined with other sources of information and experience.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?