Is what you see what you get?: Post-development auditing of methods used for predicting the zone of visual influence in EIA

Post-development auditing has been widely acknowledged as a means through which EIA could fulfill its potential to “learn from experience.” However, there remains a paucity of EIA audit research that focuses on the evaluation of specific predictive methods, and to date advances in the development of audit methodologies have been limited. In this paper a spatial approach to auditing techniques used for predicting the Zone of Visual Influence (ZVI) of projects is developed. For a series of four audit case studies, relevant ZVI predictions are tested to evaluate their accuracy and to identify the extent of impact over-prediction, under-prediction, and the occurrence of no-error (i.e., the prediction is correct). Statistical models of the residual errors (over- and under-prediction) and the no-error classification are then developed and interpreted to explore factors that explain the performance of the predictive techniques examined. Drawing on the audit findings, a framework for determining the likely accuracy of ZVI predictions is then developed based on the relationship between the precision of the predictive method and the complexity of the landscape setting. Finally, conclusions are drawn and limitations of the audit approach are highlighted.