Scientists have developed a method to accurately estimate covariance matrices in cosmology without needing a large number of simulations. By fitting a theoretical model to a smaller set of simulations, they can determine the parameters of the model. Testing their method on halo data, they found that a model covariance with just 2 free parameters can be as reliable as one built from a much larger set of simulations. They also improved upon traditional covariance matrices for halo bispectrum measurements, showing that their model is more accurate than the standard Gaussian covariance.