This document summarizes a research paper that compares the performance of different requirements engineering (RE) process models. It describes three RE process models - two existing linear models and the authors' iterative model. It also reviews literature on common RE activities and issues with descriptive models not reflecting real-world practices. The authors conducted interviews at two Indian companies to model their RE processes and compare them to the three models. They found the existing linear models did not fully capture the iterative nature of observed RE processes.