The concept of Return on Investment (ROI) in training has hitherto been largely associated with the corporate world where Kirkpatrick's model of training evaluation is widely used. Interest in Kirkpatrick is growing in the public sector. This article examines how the Kirkpatrick model is actually used in a range of commercial organisations and reports that, despite the continuing respect for the model as a whole, there are few examples of organisations moving beyond Kirkpatrick's first level evaluation. Using a grounded theory analysis of interviews with over 40 key decision-makers in a variety of businesses, the article explores what practitioners believe to be important when judging the overall effectiveness of training, and presents a five-stage holistic model for evaluating ROI based on their views and experience. The article concludes with some thoughts on the possible applicability of the five-stage model to the evaluation of public sector education and training initiatives. (Contains 1 table and 2 figures.)