Devising appropriate oversight for nanotechnology is a challenge. The field spans many scientific disciplines and product areas, capitalizing on the unusual properties and capabilities of material at the atomic scale. The critical feature of nanotechnology is not only the size at which manufacture occurs (~1-100 nanometers), but also the ability to control and manipulate the novel chemical, physical, and mechanical properties that emerge at this scale, including increased conductivity, optical properties, and reactivity. As nano-products enter the research and development (R&D) phase, hit the market, and enter consumer households, debate has emerged on oversight approaches. Regulators, manufacturers, and commentators are considering whether existing oversight systems are sufficient, those oversight systems need adjustment, or new oversight systems are needed. In order to devise recommendations for nanobio oversight, we studied the history of oversight in five related areas: genetically engineered organisms (GEOs) in the food supply, pharmaceuticals ('drugs'), medical devices, chemicals in the workplace, and gene transfer research (commonly called 'gene therapy'). Each case study was selected because of its relevance to nanobio; these case studies focus on agencies potentially involved in nanobio oversight and consider product domains in which nanobio is potentially or already active. The successes and failures of each oversight regime offer lessons to apply in developing a sound approach to nanobio oversight. The purpose of this paper is to compare the five case studies in order to derive overarching lessons for nanobio oversight. This article uses multiple disciplines and methodologies, both qualitative and quantitative, to compare our oversight case studies. In doing so, we offer a new way to evaluate oversight and derive recommendations for future oversight approaches. Part I offers background on the comparative studies and their interrelationship. Part II then discusses the methods used for comarative quantitative and qualitative research. Part III reports the results of our comparative analysis, using strengths and weaknesses of each oversight system to frame the discussion. Part IV provides further results by comparing correlations in each case study among evaluative criteria, asking what oversight system features seem to be related to one another. Part V then synthesizes the findings across case studies to identify key lessons learned from comparative analysis
