The more proximate the act, the more likely it is to be coupled with some catastrophic outcome. Proximate acts have two characteristics. They are proximate in the sense of being located in time closer to the outcome that they are alleged to have caused. Less proximate acts are those that took place farther back in time. However, this temporal dimension masks a more important aspect of proximity.
Proximate acts are the things that operators and inspectors do, for example.
It is this aspect of proximity that is reflected in empirical data showing operator error to be the most frequent officially-selected cause of many types of technological accidents. When the same hypothesis is stated in reverse, the selectivity of coupling becomes more evident. That is, the less proximate the act, the easier it is for those associated with it to resist being coupled with a disastrous outcome. The ability to deflect causal responsibility for harm roughly parallels this hierarchical arrangement. Two intervening variables further elaborate the hypothesis of proximity and causal coupling.