ABSTRACT This paper discusses the lessons learned from building a model for effort estimation. This model focuses on minimizing effort variance by enhancing the adjustments made to the functional sizing techniques. A special focus was made on the adjustment factors which reflect the application’s complexity and the actual environment in which this application will be implemented. We introduced the idea of grouping the adjustment factors to simplify the process of adjustment and to ensure more consistency in the adjustments. We have also studied, in depth, how the quality of requirements impact effort estimation. We introduced the quality of requirements as an adjustment factor in our proposed model. Our study concentrates on Egyptian companies with an objective to enhance effort estimation in these companies. We have learned a number of lessons that are discussed in the paper. From these learned lessons, we derive a group of recommendations to other researchers aiming at building similar estimation models.
