LLM-Based Automation of COSMIC Functional Size Measurement From Use Cases

COmmon Software Measurement International Consortium (COSMIC) Functional Size Measurement is a method widely used in the software industry to quantify user functionality and measure software size, which is crucial for estimating development effort, cost, and resource allocation. COSMIC measurement is a manual task that requires qualified professionals and effort. To support professionals in COSMIC measurement, we propose an automatic approach, CosMet, that leverages Large Language Models to measure software size starting from use cases specified in natural language. To evaluate the proposed approach, we developed a web tool that implements CosMet using GPT-4 and conducted two studies to assess the approach quantitatively and qualitatively. Initially, we experimented with CosMet on seven software systems, encompassing 123 use cases, and compared the generated results with the ground truth created by two certified professionals. Then, seven professional measurers evaluated the analysis achieved by CosMet and the extent to which the approach reduces the measurement time. The first study's results revealed that CosMet is highly effective in analyzing and measuring use cases. The second study highlighted that CosMet offers a transparent and interpretable analysis, allowing practitioners to understand how the measurement is derived and make necessary adjustments. Additionally, it reduces the manual measurement time by 60-80%.