= Lloyd A. Currie
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Lloyd A. Currie prepared the 1995 IUPAC recommendations on evaluating analytical methods, including detection and quantification capabilities. A central contribution was to separate an observed-result decision from the capability of a measurement process. A <detection decision threshold> controls the chance of a false positive, while a <limit of detection> also depends on the chance of missing a real signal.<Nomenclature in evaluation of analytical methods including detection and quantification capabilities by Lloyd A. Currie>[IUPAC Recommendations1995, §§3.7.2–3.7.3, especially p.1709: critical values, detection capability and error probabilities.]{ref}
An original idealized example makes the distinction visible. Suppose the blank-corrected measurement has a <normal distribution> with <standard deviation> one. A threshold near $1.645$ gives a 5% <type I error> under a zero-mean blank model. A true mean near $3.29$ places that same threshold about $1.645$ standard deviations below the mean, giving about 95% detection probability, or 5% <type II error>.
The two signal levels answer different questions: whether one observed result crosses a decision boundary, and how strong a true signal must be for reliable detection under the assumed process. These numbers belong to the stated model; they are not universal detection limits for instruments.
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