The UMIST 0.6 m diameter sieve tray column has been used with 3 systems-methanol-water, isopropanol-water and toluene-methylcylohexane-to generate, simultaneously, point efficiencies, and liquid eddy diffusion coefficients from concentration profiles, using the AIChE model. These data have been compared with the predictions of a number of published methods for predicting liquid mixing influences, to provide evidence of their accuracy and guidance in their use. The methods of AIChE and of Zuiderweg proved most accurate, with the latter recommended, for use in predicting the influence of liquid mixing on sieve trays. Point efficiencies generated were in good agreement with those previously calculated for the same runs using simple integrations of measured profiles.