How to investigate excess deaths (clip)

Investigating cause of excess deaths

In 1965, English statistician Sir Austin Bradford Hill

Causal relationships

Strength

The larger the association, the more likely that it is causal

Consistency, (reproducibility)

Consistent findings, different persons in different places

Specificity

No other likely explanation

Temporality

The effect has to occur after the cause (often with a delay)

Biological gradient, (dose response relationship)

Greater exposure should lead to greater incidence of the effect

(or indeed lower incident of effect)

Plausibility

A plausible mechanism between cause and effect

Coherence

Between epidemiological and laboratory findings

Experiment

Occasionally it is possible to appeal to experimental evidence

Analogy

Analogies or similarities between the observed association and any other associations

Reversibility

May work if there is no permanent damage