A decision rule (see game theory) that is never better than a given alternative rule. Suppose that δ₁ and δ₂ are two decision rules and that the outcome of each rule is dependent on the parameter vector θ. If, for all θ, the expected loss from using rule δ₂ is at least as large as the loss from using rule δ₁ and if it is greater for at least one θ, then the rule δ₂ is described as being inadmissible.