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Precision Templates for Ageing

May 06, 2022

These templates were designed to automate the calculation of measures of ageing precision (including percent agreement, coefficient of variance, and symmetry tests) and plot results for paired age data.

A series of templates were designed to automate the calculation of measures of ageing precision, including percent agreement and the total coefficient of variance (CV, Chang 1982), plus generating both an agreement plot and an age matrix table. Most of these measures were recommended by Campana et al. (1995). In the first two templates, an Evans & Hoenig symmetry test (Evans and Hoenig 1998) is used to test for bias if the percent agreement drops below 90 percent. The templates run in Microsoft Excel.*

Available Templates

These templates are designed to compare paired ages from one age reader, but can easily be relabeled for comparisons of two different readers or structures. Click on each title to download the corresponding template. (All files are less than 100 kb.) If clicking on the link doesn't work, try "Save Link as..."

  • Standard Precision Template
    Compares paired ages for samples with ages from 0 to 16; includes an Evans & Hoenig symmetry test.
  • 25-year Precision Template
    Compares paired ages for samples with ages from 0 to 25; includes an Evans & Hoenig symmetry test.
  • 30-year Precision Template
    Compares paired ages for samples with ages from 1 to 30.
  • 50-year Precision Template
    Compares paired ages for samples with ages from 1 to 50; also calculates percent agreement with a ±1 'forgiveness factor.'
  • Accuracy Template
    Compares test ages against known ages for samples with ages from 0 to 16.
  • Standard Symmetry Template 
    Calculates two symmetry statistics, Evans & Hoenig (diagonally-pooled) and Bowker's (unpooled) for samples with ages from 0 to 16 years and age differences up to 10 years.
  • 50-Year Symmetry Template
    Calculates two symmetry statistics, Evans & Hoenig (diagonally-pooled) and Bowker's (unpooled) for samples with ages from 1 to 50 years and age differences up to 10 years.

 

You may also download the entire set of templates (ZIP folder).

Basic instructions can be found within each template. This document (pdf, 13pg) contains detailed directions for using the standard precision template, but the directions are generally applicable for all the  precision and accuracy templates here. 

All templates were created by Sandy Sutherland at NOAA Fisheries.

 

*Use of trade or brand names in any NEFSC publication or report does not imply endorsement.

References

Campana, S. E., Annand, M. C., and McMillan, J. I. (1995). Graphical and statistical methods for determining the consistency of age determinations. Trans. Am. Fish. Soc. 124: 131-138.

Chang, W. Y. B. (1982). A statistical method for evaluating the reproducibility of age determination. Can. J. Fish. Aquat. Sci. 39: 1208-1210.

Evans, G. T., and Hoenig, J. M. (1998). Testing and viewing symmetry in contingency tables, with application to readers of fish ages. Biometrics 54: 620- 629.

 

Last updated by Northeast Fisheries Science Center on 05/06/2022

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