A factorial design was used to understand how reaction parameters such as the monomer concentration, temperature, alkyl aluminium concentration, etc. influence the reaction rate and the polymer properties on two types of metallocene catalyst systems. The polymerisation kinetics and molecular weight distribution (MWD) obtained using a novel system (catalyst supported on an activated silica) were to those obtained with the reference system (same catalyst and silica but activated with MAO). As expected, the reaction temperature and the monomer concentration are the most important factors influencing the polymerisation rate, and this is independent of the catalytic system. Otherwise, the statistical approach allowed us to identify useful levels of MAO and comonomer at which to run in order to maximise the reaction rate. (C) 2009 Elsevier B. V. All rights reserved.