Determining fundamental parameters, such as the components' radii, is one of the key aims of analysing photometric lightcurves for eclipsing binary systems. As these parameters are often used in further analysis, e.g. testing stellar evolutionary models, it is vital that these parameters are accurately obtained with suitable analysis of the uncertainties. Detrending algorithms are used to remove patterns in the systematic errors that appear the same across all stars in one field. These are often weighted in such a way that lowers the significance of high-amplitude variability in stars, and so may mask the true variability of some eclipsing binaries. How much do these detrending algorithms impact on the values determined for the parameters of the binaries? Using photometric data taken by WASP (Wide Angle Search for Planets) for five eclipsing binary systems, including the well studied binary AI Phe, correlations between the 'SysRem' detrending algorithm (used to process the WASP lightcurves) and the resulting parameters are investigated.