Over several decades, the Saint Lucian Government and several international organizations have assessed the geothermal resource within the Qualibou Caldera, Saint Lucia. Over that period of time, nine exploratory wells were drilled to find an ideal location for a geothermal electric plant; to date, a suitable location has not been discovered. Herein, a spatial subjective probabilistic decision analysis has been developed and applied to historic and contemporaneous datasets to identify a new set of exploratory locations. This simple decision methodology might, for example, benefit applied geoscientists as well as nations seeking a modicum of independence from foreign consultation. (C) 2003 CNR. Published by Elsevier Ltd. All rights reserved.