There are numerous industry resources that offer empirical and anecdotal insights on ways to maximize your ROI from trade shows. Among the more focused are:
The ROI Tool Kit web-site includes a series of simple tools to assist exhibitors in planning for an exhibition and to measure performance in delivering a return-on-investment (ROI) from exhibiting.
Center for Exhibition Industry Research
International Association of Exhibitions and Events
Society of Independent Show Organizers
Trade Show News Network