As pharma begins incorporating Web 2.0 tools in their marketing, many are unsure how to assess them. Andy Levitt, who worked for Schering-Plough, Johnson & Johnson and Genzyme before starting his own word-of-mouth marketing company, HealthTalker (healthtalker.com), coined the term “return on involvement” (ROI) to describe a new methodology.

Brand managers can’t entirely track patients’ reach to other consumers about a product like they can measure more traditional Web-based advertising or e-mail campaigns. That is, the impact of a recommendation of a friend to someone in his social network remains elusive.

But studies show word-of-mouth advertising is the most trustworthy kind. And Levitt’s ROI metric, which he is using in a customized program for Shire to raise consumer awareness about a specific disease state, will evolve over time as firms track consumers’ reach to others. The key is to embrace the new tactics now, despite the unknowns.