A variable that has attributes directly relevant to decision-making (also referred to as an ‘indicator variable’).

This occurs when there is systematic error in the techniques used to measure or record data – this could be for exposures/risk factors, outcome of interest (usually disease state), or extraneous variables (potential confounders).

The process of turning data into relevant, useable information that supports evidence-based decision-making.

Describes the degree to which study results are representative of true study population values: the ‘truth’ within the study.