Comparing IDP-Hydropathy scale against Guy's scale (A) and Kyte-Doolittle's scale (B). Each letter is the one letter code for an amino acid. Note that in Guy's scale (A), the measurement for free energy transfer adopted the opposite theme as compared to the Kyte-Doolittle scale. In Guy's scale, a positive value indicates hydrophilic, while in Kyte-Doolittle scale and IDP-Hydropathy, a positive value indicates hydrophobic. The r value is the correlation coefficient of the 2 scales compared.