This paper discusses 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 is made on the adjustment factors which reflect the application’s complexity and actual environment in which this application will be implemented. We introduce 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 impacts effort estimation. We introduce the quality of requirements as an adjustment factor in our proposed model. Our proposed model is based on three adjustment factors: “distribution”, “difficulty”, and “quality of requirements”. Our study concentrates on Egyptian companies with an objective to enhance effort estimation in these companies.