In this age of high technology, the expert consultant usually must state an opinion based on limited information. This is especially true in construction defect or delay claim cases, or when the damage to a structure is due to the Occurrence of a natural phenomenon such as rainstorms, strong winds, or earthquakes. The ever expanding availability of tools for computer analysis of structures enable increasing insight and improved accuracy in helping to understand the cause of damage, but many of these analyses are very expensive. Often the client and the expert face the dilemma of balancing the expenditure of limited funds with the goal of achieving a desired level of confidence in the expert's opinion. This paper addresses how one can scientifically assess the confidence in an experts' opinion. Copyright (C) 2007 John Wiley & Sons, Ltd.