A new approach is proposed to cross-check conflicting measured values of the thermodiffusion coefficients in ternary mixtures. The results of recent measurements performed in ternary mixture of hydrocarbons 1,2,3,4-tetrahydronaphthalene, isobutylbenzene, and dodecane by thermogravitational column [P. Blanco, M. M. Bou-Ali, J. K. Platten, D. A. de Mezquia, J. A. Madariaga, and C. Santamaría, J. Chem. Phys. 132, 114506 (2010)] and optical beam deflection [A. Königer, H. Wunderlich, and W. Köhler, J. Chem. Phys. 132, 174506 (2010)] are critically analyzed. A way of matching them into a unique value is reported. The accuracy of the integrated value should significantly exceed that of the original results. Two diagnostics are required to determine thermodiffusion coefficients in ternary mixture, e.g., two different wavelengths or density and refractive index. It is shown that by attributing a reliability weight for each pair of diagnostics among the available techniques the best combination can be selected. The true values of thermodiffusion coefficients are extremely sensitive to the knowledge of precise values of mass diffusion coefficients and contrast factors.