A recent paper [Y. Q. Zhang, B. J. Chen, S. Xu, X. P. Li, J. S. Zhang, J. S. Sun, X. Q. Zhang, H. P. Xia and R. N. Hua, A universal approach for calculating the Judd–Ofelt parameters of RE³⁺ in powdered phosphors and its application for the β-NaYF₄:Er³⁺/Yb³⁺ phosphor derived from auto-combustion-assisted fluoridation, Phys. Chem. Chem. Phys., 2018, 20, 15876–15883] used the Er³⁺/Yb³⁺:β-NaYF₄ phosphor as an example to demonstrate a method used for evaluating Judd–Ofelt parameters of rare-earth-ion-doped powder. The method is actually established on the basis of a measured diffuse reflectance spectrum and fluorescence lifetime of Er³⁺ emission at 1.5 μm. The paper compared the Judd–Ofelt parameters obtained from two least-squares fitting processes with and without inclusion of two strong Er³⁺ absorption transitions from ⁴I_15/2 to ²H_11/2 and ⁴G_11/2, and erroneously concluded that the values of the Judd–Ofelt parameters depend mainly on the majority of transitions with even weak intensities rather than on a few strong transitions. We have repeated the two fitting processes and the reverse conclusion has been made. Moreover, we have studied the effects of the transitions selected for the analysis and comprehensive explanations are given for the effects. In addition, the previously reported methods, including the aforementioned one, are reviewed, compared and discussed in detail.