A marked anti-correlation between the degree of linear polarisation dL and the intensity I, has been reported for some pulsars (Manchester, Taylor & Huguenin 1975; Xilouris et. al. 1994). A detailed investigation of the variation in the total polarisation of single pulses for some pulsars has been done, with proper statistical correction applied to the linearly polarised power. This study, then, reveals very different behaviour as well as some remarkable correlations in many pulsars, which reflect directly on the nature of pulsar radio emission.

The most important correction to be applied to linear polarisation data arises from the differences in the statistical properties of the Stokes parameters Q and U, defining the linear polarisation, and the linearly polarised power The measured value of the linearly polarised power is larger than the true value, with the difference being , where σ is the measured standard deviation in the off-pulse region in any of the Stokes parameters (Rankin, Campbell & Spangler 1975).