Hillkriteriene

Hillkriteriene, or Hill's criteria for causation, are a set of nine guidelines introduced by the epidemiologist Austin Bradford Hill in 1965 to help judge whether an observed association between a factor and a disease is causal. They are intended as a framework for weighing evidence in epidemiology and are not an inflexible checklist or definitive proof.

The nine criteria are: strength of the association; consistency across different studies and populations; specificity of the association; temporality, meaning exposure must precede the outcome; biological gradient or dose–response relationship; plausibility within existing biological or scientific knowledge; coherence with current theory and knowledge; the potential for experimental evidence, such as intervention effects; and analogy with known causal relationships. Each criterion highlights a different aspect of causal reasoning, from how large an effect is to how well it fits with what is already known.

Usage and limitations: The criteria are guidelines rather than strict rules. Temporality is generally considered essential, while specificity is less applicable for multifactorial diseases. In modern practice, Hill's criteria are used alongside formal causal inference methods to interpret observational data and communicate uncertainty. They inform public health thinking but do not replace experimental evidence or rigorous statistical analysis.

Classic examples often cited include the smoking–lung cancer relationship, where several criteria align with a causal interpretation. Hillkriteriene remain influential in discussions of causality in epidemiology and public health.