SF efficiency as a function of the velocity dispersion of the clumps (σ_v,clumps) across the merger sequence. From left to right and top to bottom, the merger stages are isolated galaxies (blue), galaxy pairs (red), early-stage mergers (orange), mid-stage mergers (magenta) and late-stage mergers (black). The Spearman’s rank correlation coefficients (ρ_s) are indicated. The bottom right panel shows the mean values of log₁₀SFE_clumps and σ_v,clumps for each merger stage; the error bars represent the mean absolute deviation.