Further comparison of cross-company and within-company effort estimation models for Web applications

This paper extends a previous study, using data on 67 Web projects from the Tukutuku database, investigating to what extent a cross-company cost model can be successfully employed to estimate effort for projects that belong to a single company, where no projects from this company were used to build the cross-company model. Our within-company model employed data on 14 Web projects from a single Web company. Our results were similar to those from the previous study, showing that predictions based on the within-company model were significantly more accurate than those based on the cross-company model. We also found that predictions were very poor when the within-company cost model was used to estimate effort for 53 Web projects from different companies. We analysed the data using two techniques, forward stepwise regression and case-based reasoning. We found estimates produced using stepwise regression models were better for the within company model while case-based reasoning predictions were better for the cross-company model.