This paper presents a comparison of various methods for absolute structure refinement using single-crystal X-ray diffraction data for 23 crystals with no element heavier than oxygen. The methods tested include conventional refinement using an inversion twin model, intensity quotient estimation in SHELXL2012, Bayesian estimation in PLATON, numerical intensity difference restraints in CRYSTALS, and quotient and difference restraints in TOPAS-Academic. The Flack parameter, which indicates the degree of inversion twinning in a crystal, was determined with varying precision across these methods. Conventional refinement provided accurate values but with higher standard uncertainties, while the other methods yielded more precise results. All methods successfully determined the absolute structure, even for hydrocarbons. The Flack parameter is a critical indicator of the absolute structure of a crystal, and its precision is influenced by the magnitude of resonant scattering effects, which depend on the chemical elements present and the X-ray wavelength used. For many organic compounds, especially those with light atoms, the Flack parameter is difficult to determine precisely due to small resonant scattering effects. The paper highlights the importance of low random and systematic errors in intensity measurements for accurate Flack parameter determination. The study demonstrates that methods incorporating intensity differences and quotients allow the Flack parameter to be refined along with other structural parameters, leading to more precise estimates. This approach avoids the potential criticisms of conventional methods and provides a more realistic assessment of the Flack parameter's standard uncertainty. The results show that the Flack parameter can be determined with sufficient precision for many organic compounds, even when resonant scattering effects are small. The paper also discusses the use of invariom models and other techniques to improve the precision of absolute structure determination. Overall, the findings support the use of post-refinement algorithms for absolute structure determination when complete Friedel pair intensity measurements are available.This paper presents a comparison of various methods for absolute structure refinement using single-crystal X-ray diffraction data for 23 crystals with no element heavier than oxygen. The methods tested include conventional refinement using an inversion twin model, intensity quotient estimation in SHELXL2012, Bayesian estimation in PLATON, numerical intensity difference restraints in CRYSTALS, and quotient and difference restraints in TOPAS-Academic. The Flack parameter, which indicates the degree of inversion twinning in a crystal, was determined with varying precision across these methods. Conventional refinement provided accurate values but with higher standard uncertainties, while the other methods yielded more precise results. All methods successfully determined the absolute structure, even for hydrocarbons. The Flack parameter is a critical indicator of the absolute structure of a crystal, and its precision is influenced by the magnitude of resonant scattering effects, which depend on the chemical elements present and the X-ray wavelength used. For many organic compounds, especially those with light atoms, the Flack parameter is difficult to determine precisely due to small resonant scattering effects. The paper highlights the importance of low random and systematic errors in intensity measurements for accurate Flack parameter determination. The study demonstrates that methods incorporating intensity differences and quotients allow the Flack parameter to be refined along with other structural parameters, leading to more precise estimates. This approach avoids the potential criticisms of conventional methods and provides a more realistic assessment of the Flack parameter's standard uncertainty. The results show that the Flack parameter can be determined with sufficient precision for many organic compounds, even when resonant scattering effects are small. The paper also discusses the use of invariom models and other techniques to improve the precision of absolute structure determination. Overall, the findings support the use of post-refinement algorithms for absolute structure determination when complete Friedel pair intensity measurements are available.