Research into the subjective perception of risk generally involves asking study participants to rate a heterogeneous set of environmental or health risks including risks from individual activities, residential or work conditions, hazards from technologies, substances or products, and natural hazards. Respondents are asked to rate these activities or hazards in terms of perceived magnitude of risk, the acceptability of the risk and other aspects such as likelihood of death, catastrophic potential, avoidability, fear, familiarity, imposed or personal choice, time scale of impact, benefits of risk source, degree of concern, personal exposure etc.