Safety in numbers is the theory that by being part of a large group, an individual member is proportionally less likely to be the victim of a mishap, accident, or other bad event.

Examples of safety in numbers include flocks of birds and shoals of fish. In both of these instances, by being part of a large group, individuals face reduced risk of falling victim to predators than they would if operating independently.

Safety in numbers is also used to describe the theory that higher numbers of cyclists using the roads in a given area improves their safety (perhaps by increasing the "awareness" of motor vehicle drivers). While at least one study claims to have shown that the former causes the latter, that study did not use data collection methods which would properly allow a causal relationship to be established.

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Evolutionary biology | Social psychology | Statistics | Cycling safety