Cooperative spontaneous emission, or superradiance, occurs when a group of excited atoms emit light coherently in an intense burst due to synchronized dipole moments. This phenomenon is significant for applications in spectroscopy, metrology, and high-brightness light sources. Modeling such collective emission is challenging for large atomic systems, prompting the development of efficient numerical frameworks. This dissertation introduces a second quantized formalism in Liouville space and a stochastic approach based on the positive P representation. These methods are applied to study compact systems of multi-level emitters under incoherent pumping and decoherence. Numerical results benchmark the two approaches and highlight their utility and limitations for simulating many-body quantum effects.