Guidelines for Statistical Usage in Age-Estimation Technics

Most papers concerned with age-estimation technics contain procedural or statistical errors or omissions that hinder efforts to evaluate their accuracy and hence their worth. Eight common problems are cited: (1) reconciliation of variability in counts of annuli within an individual, (2) lack of known-age material, (3) inadequate statistical treatment; and, for regression analysis, (4) heteroscedasticity, (5) nonlinearity, (6) confusion over the identity of the dependent variable, (7) assessing accuracy of the technic, and (8) confidence limits. Recommendations are given to avoid these problems and to improve the quality of future age-estimation literature. J. WILDL. MANAGE. 44(3):541-548 In the past 20 years, many publications have dealt with age-estimation technics. However, many of these papers are of questionable value for future workers, not because of the technics themselves, but because authors failed to provide useful estimates of the accuracy of their technics. This problem frequently is due to the omission of statistical treatment; less often, invalid or illogical procedures are used in analyzing data. Even casual perusal of recent literature in this field reveals an obvious need for suggestions concerning proper analysis and presentation of data. I have no wish to criticize specific authors, and will not intimate guilt by citing them in the following discussion; to do so would accomplish nothing of a positive nature. My intent is to describe and explain 8 types of problems evident in the literature so that future researchers might be stimulated to present their work with maximum effec-