AbstractThe paper expands on an interesting phenomenon accompanying large‐scale projects, namely, the parallel inflation in costs and deflation in benefits from initiation to implementation and final evaluation or elimination altogether. Historically, three explanations have been provided for the above phenomenon: the deterministic effects of uncertainty; self‐interest evaluators; and the ‘vision’ factor. We claim that on face value one cannot accept as scientifically sound evidence the above three explanations of the constant decline in actual benefits. The ‘acceptance‐avoidance’ model which we bring to bear predicts a constant deterioration in actual benefits as the project develops. This psychological factor results in the use of the three above‐mentioned explanations as a ‘cover‐up’ for real underlying human doubts regarding the chances of success of crucial decisions