The conformational preference of an equatorial compared to an axial substituent in a monosubstituted cyclohexane. This steric substituent parameter equals \(\Delta _{\rm{r}}G^{\,\unicode{x26ac}}\) in \(\pu{kcal mol-1}\) for the equatorial to axial equilibration on cyclohexane. The values are also known as 'Winstein–Holness' A values.