The electron mobility in In0.53Ga0.47As is calculated using both relaxation-time-approximation and variational-principle approaches and compared with that calculated by the Matthiessen rule method and with experiment. By using either the compensation ratio or alloy scattering potential, or both, as fitting parameters, all three techniques can be brought to good agreement with experimental data for carrier concentration in the 5 x 10(15)-1 x 10(17) cm-3 range. The fitted parameters are also shown to be comparable across the different techniques used and with those determined experimentally. Using all three methods, the effect of compensation on electron mobility at 77 and 300 K is also calculated as a function of net electron density. These curves are then compared with the multitude of experimentally determined mobilities in In0.53Ga0.47As grown by various techniques. In general, the use of the variational principle to calculate electron mobility give only slightly better correlation with experiments than the more approximate methods.