An Under Estimate (or Underestimate) is to fail or mistake to guess or understand the real cost, size, difficulty, etc., or to consider or think lower in ability, influence, or value than actual that is too low because of the lack of information, skills, knowledges or experiences. The Under Estimate of resources and costs is one of the most common contributors to the project failure. (Opposite of the Over Estimate)

Related Definitions in the Project: The Project Controls; The Cost Estimate (Estimation); Project Management