Realistic theoretical models of quantum well laser performance at both short wavelengths in GaAs/GaAlAs and long wavelengths in InP matched materials have been shown to require a degree of relaxation of the k-selection rule for the optical transition in order to match experimentally obtained spectral gain curves. This can be achieved by the inclusion of lifetime broadening into the calculation of the spectral dependence of the gain. As is discussed, parameters of device performance such as threshold current, gainslope and linewidth enhancement factor are also sensitive to the degree of broadening so that it is important to have a good understanding of the different mechanisms contributing to the broadening energy. The origin of this broadening may lie in both accidental material variations, well width fluctuations for example, or in intrinsic broadening mechanisms such as electron-electron scattering. This paper concludes by introducing results from a relatively simple calculation of the lifetime broadening due to electron-electron interactions for a state in a single parabolic band. Results for 3D systems and 2D systems in the infinite well depth limit are compared and it emerges that the broadening is somewhat enhanced in the 2D system.