Northeast Fisheries Science Center reference document ; 06-28

"In production aging programs, age reader accuracy can be thought of as how often the 'right' age is obtained, and precision as how often the 'same' age is obtained (Campana 2001). It is possible that, over time, an age reader may inadvertently change the criteria that are used for determining ages, thereby introducing a bias into the age data. This bias can be measured with accuracy tests, which consist of the age reader blindly examining known- or consensus-aged fish from established reference collections. An age reader may also make periodic mistakes, which introduces random errors into the data. The degree of this error can be measured with precision tests, which consist of the age reader blindly re-aging fish which they have already aged. Both accuracy and precision must be considered within a quality-control monitoring program"-- Introduction.

National Marine Fisheries Service (NMFS)

Atlantic Coast (U.S.)