[en] Various statistical computing formulas have been used to estimate the transfer of radionuclides from one environmental component to another. The parameter being estimated is the ratio μ_Vμ_U, where μ_U is the true mean concentration of the donor component (e.g., soil), and μ_V is the true mean concentration of the receiving component (e.g., vegetation). In radionuclide research μ_Vμ_U may be the concentration ratio (CR) or the inventory ratio (IR). A Monte Carlo computer simulation study in conjunction with mathematical derivations of bias and root expected mean square was conducted to provide guidance on which of eight estimators (computing formulae) are most likely to give the best estimate of μ_Vμ_U. These estimators were evaluated for both laboratory and field studies when data are normally or lognormally distributed