Abstract: In this talk, we examine the total stellar-to-halo mass ratio as a function of halo mass for a new sample of simulated field galaxies using fully cosmological, I>CDM, high resolution SPH + N-Body simulations carried to the present time. These simulations include explicit H2 and metal cooling, star formation (SF) and supernovae (SN) driven gas outflows. We find extremely good agreement between the simulations and predictions from the statistical Halo Occupation Distribution model presented in Moster et al. (2012). This is due to a combination of systematic factors: a) gas outflows that reduce the overall SF efficiency b) estimating the stellar masses of simulated galaxies using artificial observations and photometric techniques similar to those used in observations. Our analysis provides an excellent match to previous observational estimates and suggests that stellar mass estimates based on photometric magnitudes underestimate the contribution of old stellar populations to the total stellar mass, leading to stellar mass errors of up to 50% for individual galaxies. These results highlight the importance of using proper techniques to compare simulations with observations and reduce the perceived tension between the star formation efficiency in galaxy formation models and in real galaxies.