The present work is based on the fact that site effectiveness is a relevant value when analysing the suitability of a location for constant-speed wind turbines. An analytical expression is developed to calculate the said effectiveness by means of a potential adjustment model to the ascending segment of the power curve in pitch regulated wind turbines. Upon analysis of the results obtained for maximum effectiveness in a given location, using both the potential model and the quadratic model applied in earlier studies, no significant differences were observed in wind conditions of interest for wind energy applications. Notwithstanding, when the cut-in wind speed was compared, corresponding to the maximum effectiveness values at the same location according to the two models indicated, noticeable differences were observed. It can therefore be deduced that, when selecting this design parameter, a careful study should be made in order to determine which model best fits the power curve of the wind turbine under analysis for a specific location. (C) 2003 Elsevier Science Ltd. All rights reserved.