Predicting successful implementation of enterprise resource planning (ERP) systems is still an elusive problem. The cost of ERP implementation failures is exceedingly high in terms of quantifiable financial resources and organizational disruption. The lack of good explanatory and predictive models makes it difficult for managers to develop and plan ERP implementation projects with any assurance of success. In this paper we investigate the Klein & Sorra theoretical model of implementation effectiveness. To test this model we develop and validate a data collection instrument to capture the appropriate data, and then use multivariate adaptive regression splines to examine the assertions of the model and suggest additional significant relationships among the factors of their model. Our research offers new dimensions for studying managerial interventions in IT implementation and insights into factors that can be managed to improve the effectiveness of ERP implementation projects.