Study Abstract: Practitioners of clinical trials have a responsibility to ensure that patients participation in research is informed and voluntary. This implies that we should continuously strive to improve the effectiveness of methods for informing prospective research volunteers about experimental studies, thereby enhancing the likelihood that their interests are respected. Innovations in informed consent should be tested in realistic contexts (i.e., in clinical trials) and when appropriate with randomization at the first opportunity. In this proposed project we take efforts to improve the quality of informed consent, based on experimentation with informed consent in ongoing clinical trials in the VA Cooperative Studies Program. The CSP is uniquely situated to serve as a testing ground for informed consent, not only because of concerns for enhancing consent for human experimentation, but also because of the centralized coordination of wide variety of clinical studies representing an extraordinary range of patient capacities and vulnerabilities. Moreover, such an effort is a special responsibility of the VA given the profound trust placed in the research enterprise by veterans.