Are there patterns in how coefficients of variation (CV's) vary across taxonomic group, age class, or survey method? Here's a breakdown of mean CV's according to such variables from the annual surveys contained in the Amphibian Count CV Tool. More specific cross-variable analyses can be made at that site, where the mean CV is given for every search.

A CV is calculated by dividing the standard deviation by the mean. To remove the effects of trend over time, we used the standard deviation of the residuals from a regression of the counts against time. Associated with this method are inherent assumptions which you may find disagreeable due to sticky statistical issues like model misspecification, autocorrelation, and effect of survey length on variance. For this reason, we include raw counts in the database for you to analyze with your preferred method.