This study presents a systematic comparison of two alternative measures of citizens' perceptions of risks and benefits of emerging technologies. By focusing on two specific issues (nanotechnology and biofuels), we derive several insights for the measurement of public views of science. Most importantly, our analyses reveal that relying on global, single-item measures may lead to invalid inferences regarding external influences on public perceptions, particularly those related to cognitive schema and media use. Beyond these methodological implications, this analysis suggests several reasons why researchers in the area of public attitudes toward science must revisit notions of measurement in order to accurately inform the general public, policymakers, scientists, and journalists about trends in public opinion toward emerging technologies.
Keywords: public consultations; public understanding of science; risk perception; science communication; science policy.