SUMMARYThe correlation between dimensionless shear φ m and dimensionless height z/L, where L is the Obukhov length, for stable conditions is strongly influenced by self-correlation for the present datasets. This effect is quite large for stronger stability but still significant for near-neutral conditions. A conditional analysis of nocturnal stable boundary-layer data, where 'non-turbulent' parts of the record are removed, reduces the impact of nonstationarity and therefore reduces the scatter. The conditional analysis also reduces the relative importance of self-correlation. Difficulties with estimating self-correlation are also discussed.