  I discuss two of the possible sources of biases in the determination of the
IMF: binning and the existence of unresolved components. The first source is
important for clusters with a small number of stars detected in a given mass
bin while the second one is relevant for all clusters located beyond the
immediate solar neighborhood. For both cases I will present results of
numerical simulations and I will discuss strategies to correct for their
effects. I also present a brief description of a third unrelated bias source.
