Aging Experience, Accuracy, and Precision

Matson’s experience level varies among different mammal species. We currently process approximately 90,000 – 100,000 teeth annually with a trend of steady increase. Last tabulated through December 2018, the count of teeth aged in our laboratory was 2,546,500, broken down by species as follows:

To encourage continuing accuracy evaluation, Matson’s processes all teeth from known age animals without charge, providing the results can be shared in our periodic reports. Although we continue to collect accuracy and precision data, a thorough tabulation has not been made since 1998 and we expect new data to differ very little from those presented here. Known age material is not available to fully evaluate accuracy in most species, with exceptions being Alaska brown bear and Rocky Mountain elk.

Cementum aging accuracy can be expected to vary not only among different species and populations, but also among individuals in the same population. However, the evidence below indicates that most species should be aged with an accuracy of 70%, and 90% will be within 1 year of the correct age. For species that are difficult to analyze, 50% should be aged accurately and 85% will be within 1 year of the correct age.

Species with the most distinct cementum annuli occurring in the most regular pattern are expected to be the most accurately aged.
The following groupings reflect expected aging accuracy based on cementum characteristics.

*Populations are variable, with some having cementum characteristics that yield high accuracy (e.g. Rocky Mountain elk, northern deer populations) and others that yield moderate accuracy (e.g. southern whitetail deer, southwestern mule deer, coastal elk). Supplementally fed animals have cementum annuli that are more complex and irregular than wild populations, which may lower the reliability of age analysis. For more information about supplemental feeding, see the Accuracy section of our Hunter & Outfitter page.

To encourage continuing precision evaluation, Matson’s processes blind duplicates without charge, providing the results can be shared in our periodic reports. We will analyze a number of blind duplicates totaling up to 10% of the sample size, not to exceed 50 teeth (e.g. in a sample of 100 teeth, 10 blind duplicates will be processed free of charge). Although we continue to collect precision data, a thorough tabulation has not been made since 1998. Ongoing evaluations show precision continuing at levels observed in the past.

In the absence of known age teeth, precision measurements using blind pairs provide useful information because differing results for a pair are proof of error. Results of precision tests with blind duplicates follow (please note that accuracy for these species is expected to be moderate or low because of cementum characteristics).