  Odd-even effects, also known as "staggering" effects, are a common feature
observed in the yield distributions of fragments produced in different types of
nuclear reactions. We review old methods, and we propose new ones, for a
quantitative estimation of these effects as a function of proton or neutron
number of the reaction products. All methods are compared on the basis of Monte
Carlo simulations. We find that some are not well suited for the task, the most
reliable ones being those based either on a non-linear fit with a properly
oscillating function or on a third (or fourth) finite difference approach. In
any case, high statistic is of paramount importance to avoid that spurious
structures appear just because of statistical fluctuations in the data and of
strong correlations among the yields of neighboring fragments.
