 Research Plan : A single blind, cluster randomized controlled trial will be conducted to test the hypothesized benefits of the targeted psychotropic drug alert and recommendation system versus the standard automated generic drug alert system within a fixed cohort of primary care physicians and an open cohort of patients seen by study physicians in the 16 month follow-up period for the assessment of reductions in potentially inappropriate psychotropic prescriptions and fall-related injuries. A single blind trial was planned because intervention status cannot be blinded for physicians in the study. However, study participants are blinded to the outcomes assessed, because the data required to assess these outcomes can be predominantly collected and assessed using data sources that are independent of the intervention status. Patients, clustered within physicians, is the unit of analysis because patient level information provides the most precise, non-ecological, method of the study outcomes as well as potential confounders, and because hierarchical multivariate analytic methods are now available to model clustering in the assessment of treatment effectChuang, 2000 4339 id. The benefit of the intervention will be assessed by comparing patients of physicians who received the psychotropic drug alert and recommendation system and patients of physicians who received automated drug decision support. This approach minimizes Hawthorne effects, arising from the intensive nature of practice intervention required to support computer-based systems in primary care that would likely result in over-estimation of benefit if computer-based decision support for drug management were compared to physicians with no computerized intervention. Further, it provides a means by which information on prescriptions, drug and disease profile can be assessed in an equivalent way between patients of physicians with automated control or targeted alert experimental decision-support, reducing biases related to differences in measurement sources. 