Authors
Shawn
R. Narum
Report Reference
#Conservation
Genetics
(2006) 7:783-787
Publication Date
4 September
2005
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Beyond
Bonferroni: Less conservative analyses for conservation genetics
Abstract |
| Studies
in conservation genetics often attempt to determine genetic differentiation
between two or more temporally or geographically distinct sample collections.
Pairwise p-values from Fisher’s exact tests or contingency
Chi-square tests are commonly reported with a Bonferroni correction
for multiple tests. While the Bonferroni correction controls the experiment-wise
α, this correction is very conservative and results in greatly
diminished power to detect differentiation among pairs of sample collections.
An alternative is to control the false discovery rate (FDR) that provides
increased power, but this method only maintains experiment-wise α
when none of the pairwise comparisons are significant. Recent modifications
to the FDR method provide a moderate approach to determining significance
level. Simulations reveal that critical values of multiple comparison
tests with both the Bonferroni method and a modified FDR method approach
a minimum asymptote very near zero as the number of tests gets large,
but the Bonferroni method approaches zero much more rapidly than the
modified FDR method. I compared pairwise significance from three published
studies using three critical values corresponding to Bonferroni, FDR,
and modified FDR methods. Results suggest that the modified FDR method
may provide the most biologically important critical value for evaluating
significance of population differentiation in conservation genetics.
Ultimately, more thorough reporting of statistical significance is
needed to allow interpretation of biological significance of genetic
differentiation among populations. |
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(136
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