Effort Prediction for Microservices: A Case Study

Software size measurement is critical as an input to perform important project management processes such as effort, cost and schedule estimation. Functional size measurement (FSM) methods are beneficial in terms of being applicable in the early phases of the software life cycle over functional requirements and providing a systematic and repeatable method. However, in agile organizations, it can be challenging to seperate measurement components of FSM methods from requirements in the early phases as the documentation is kept to a minimum compared to traditional methods such as the Waterfall Model and is detailed as the project steps. In addition, the existing FSM methods are not fully compatible with today's architectural structures, which are from being data-driven and to evolve into a behaviour-oriented structure. In this study, we performed a case study which includes a project developed with agile methods and using microservice-based architecture to compare the effectiveness of COSMIC FSM and event-based software size measurement. For this purpose, we measured the size of the project and created effort estimation models based on two methods. The measurers had difficulty in applying both methods due to the limited detail level of the requirements in the project. However, the event-based method was found to estimate effort with less error than the COSMIC FSM method.