In risk comparisons in particular, a risk is frequently defined as multiplication of the extent of the consequences of an occurrence by the frequency (probability) of its occurrence. For example a technology with frequently occurring accidents, but limited consequences (e.g. car) may present higher risks than a technology with rare, but serious accidents (aircraft). This risk variable is the benchmark for assessment of possible consequences of a technology and for comparison of consequences of various technologies. It should be noted that risk can be evaluated for both adverse consequences (threats) and desirable consequences (opportunities).