Before revision:  We find that the 3/2 plus jumps model is more parsimonious than competing models from its class;
After revision:  The pure-diffusion model, however, struggles to reproduce the smile in the implied volatilities of short-term index options. One remedy to this problem is to augment the model by introducing jumps in the index. The resulting 3/2 plus jumps model is more parsimonious than competing models from its class;