Performance evaluation of general and company specific models in software development effort estimation

In this paper we present the results of our effort estimation analysis of a European Space Agency database consisting of 108 software development projects. We develop and evaluate simple empirical effort estimation models that include only those productivity factors found to be significant for these projects and determine if models based on a multicompany database can be successfully used to make effort estimations within a specific company. This was accomplished by developing company specific effort estimation models based on the significant productivity factors of a particular company and by comparing the results with those from general ESA models on a holdout sample of the company. To our knowledge, no other published research has yet developed and analysed software development effort estimation models in this way. Effort predictions made on a holdout sample of the individual company's projects using general models were less accurate than the company specific model. However, it is likely that in the absence of enough resources and data for a company to develop its own model, the application of general models may be more accurate than the use of guessing and intuition.