Pairwise distributions of the normalized lag differences among the three spectral-lag estimation methods. For each pair of methods, the normalized lag difference is defined as $({\tau }_i-{\tau }_j)/\sqrt{{\sigma }_i^2+{\sigma }_j^2}$, where τ_i and τ_j are the lag estimates and σ_i and σ_j are their corresponding uncertainties. The dashed line marks the mean value of each distribution. The quoted uncertainties of the mean values and standard deviations are estimated from bootstrap resampling of the GRB sample. Overall, the three methods are consistent with each other, with no significant differences found within 3σ.