  Behavioral science has witnessed an explosion in the number of biases
identified by behavioral scientists, to more than 200 at present. This article
identifies the 10 most important behavioral biases for project management.
First, we argue it is a mistake to equate behavioral bias with cognitive bias,
as is common. Cognitive bias is half the story; political bias the other half.
Second, we list the top 10 behavioral biases in project management: (1)
strategic misrepresentation, (2) optimism bias, (3) uniqueness bias, (4) the
planning fallacy, (5) overconfidence bias, (6) hindsight bias, (7) availability
bias, (8) the base rate fallacy, (9) anchoring, and (10) escalation of
commitment. Each bias is defined, and its impacts on project management are
explained, with examples. Third, base rate neglect is identified as a primary
reason that projects underperform. This is supported by presentation of the
most comprehensive set of base rates that exist in project management
scholarship, from 2,062 projects. Finally, recent findings of power law
outcomes in project performance are identified as a possible first stage in
discovering a general theory of project management, with more fundamental and
more scientific explanations of project outcomes than found in conventional
theory.
