The Protection Motivation Theory proposes that the intention to protect one self depends upon four factors:
1) The perceived severity of a threatened event (e.g., a heart attack)
2) The perceived probability of the occurrence, or vulnerability (in this example, the perceived vulnerability of the individual to a hear attack)
3) The efficacy of the recommended preventive behavior (the perceived response efficacy)
4) The perceived self-efficacy (i.e., the level of confidence in one’s ability to undertake the recommended preventive behavior).