Douglas Jay Klein and other researchers have seen that there is a great potential in applying partial order in the field of QSAR.The basic idea is to deduce from order relations among chemicals, properties of the ordered chemicals.Despite the satisfactory results found by Klein's methods, we think it is worth exploring another feature of the poset of chemicals used in Klein's approaches, namely the average posetic height, h av , of each chemical.In the current paper we explore some methods to calculate these heights and use them as independent variables for modelling a chemical property that is also modelled by Klein's approaches, namely octanol / water partition coefficient K OW .It turned out that the application of average heights, h av , as predictors of a linear log K OW estimation leads to reasonable results in the application example of chlorophenols.(