Validation of Supplier Estimates Using COSMIC Method Francisco Valdés-Souto National Autonomous University of Mexico Science Faculty CDMX, Mexico City, Mexico fvaldes@ciencias.unam.mx ORCID: 0000-0001-6736-0666 Abstract. In the software development industry, it is well known that software development organizations (suppliers) need a better and formal estimation ap- proaches in order to increase the success rate of software projects developed. Considering a systematic view, any project requested by a customer needs to be validated in the estimation provided by the supplier, regardless of how formal or not the estimation method utilized was. However, very often the customers do not know the information used by the sup- pliers to make their estimations. The software decision makers must face a vali- dation estimates problem where the more useful solution is used the expert judg- ment, with several problems related to it. In this paper, a real case study is described where a validation estimates model was generated from a reference database based in COSMIC method. The defined model using a density function helps to the customer to define validation criteria considering the probability that the supplier estimate will be met according to an industry reference database. Keywords. COSMIC ISO 19761, FSM, Software Estimation, Validation Esti- mates. 1 Introduction In the competitive software development industry, it is well known that software de- velopment organizations need a better and formal estimation approaches in order to increase the success rate of software projects. In the literature several techniques and models have been proposed to improve the estimation capabilities in software projects over decades. However, most of the ap- proaches and techniques have been proposed considering a development organization point of view. [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12] For decades considerable research has been directed at building and evaluating soft- ware effort estimation methods and tools for the organization to develop software pro- jects. The estimation accuracy is a major factor for accepting or declining the estimation methods. [11], [12] 15 Copyright © 2019 for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).