  We present a study of the results obtained combining LO partonic matrix
elements with different orders of partons distributions. These are compared to
the best prediction using NLO for both matrix elements and parton
distributions. The aim is to determine which parton distributions are most
appropriate to use in those cases where only LO matrix elements are available,
e.g. as in many Monte Carlo generators. Both LO and NLO parton distributions
have faults so a modified optimal LO set is suggested.
