Mining project feasibility studies have historically underestimated costs and timeframes, with an average cost overrun of 22% found in a study of 60 projects from 1980 to 2001. The issues are complex, as mining is an inexact science that relies heavily on human experience. Studies can also be manipulated to achieve desired outcomes and emphasize controllable factors over uncontrollable risks like commodity prices and inflation. Politics and pressure from management and shareholders to show positive results can further compromise the objectivity of feasibility studies. Improving processes to manage risks and people, rather than just the numbers, is needed to avoid cost overruns that could significantly impact company finances long-term.