• Reliability is (1) An actuarial term that describes the degree of accuracy in predicting future events based on statistical reporting of past events. (2) A weight given or assigned to observable data as opposed to that given to an external or larger set of data. data. Confidence is used to provide a measure of the relative predictive value of the analyzed data. Weights can be determined using detailed formulas or judgment. Assigned weights should generally increase with the number of effect bases in the observed data and should decrease with higher levels of observed data variability.