Bias in project performance causes schedule and cost to overrun baseline estimates (your model). Bias is the onesided tendency of actual schedule or cost to overrun the model. A Guide to the Project Management Body of Knowledge (PMBOK® Guide) and supporting literature recommend estimating the variability for all project time and cost estimates, and sizing appropriate schedule or cost buffers (also known as contingency or management reserve) using Monte-Carlo analysis or PERT. This paper describes a number of sources of bias in performance of projects to schedule and cost estimates, and provides recommendations to size buffers that ensure your projects come in under your baseline schedule and budget.
CII (Construction Industry Institute). (1989). Management of project risks and uncertainties (CII Publication 6-8). Austin, TX: University of Texas at Austin.
2.
FordD. N., & StermanJ. D. (1998). Overcoming the 90% syndrome: Iteration management in concurrent development projects.Retrieved January 2002 from MIT Web site. Cambridge: MIT
JohnsonJ. (1999, December). CHAOS into success. Software Magazine.
5.
KahnemanD., SlovicPaul, & TverskyAmos (1982). Judgment under Uncertainty: Heuristics and bias.New York: Cambridge University Press.
6.
LeachL. P. (2000). Critical chain project management.Boston: Artech House.
7.
LeachL. P. (2001). Putting quality in project risk management. PM Network (February), p. 53.
8.
MalcolmD. G., RosebloomJohn H., ClarkCharles E., & FazarWillard (1959). Application of a Technique for Research and Development Program Evaluation. Operations Research (September), p. 646.
9.
MeredithJ. R., & MantelS. J. (1995). Project management: A managerial approach (3rd ed.).New York: John Wiley.
10.
MorganM. G., & HenronMax (1990). Uncertainty, A guide to dealing with uncertainty in qualitative risk and policy analysis.Cambridge University Press: New York.
11.
Project Management Institute (PMI). (2000). A guide to the project management body of knowledge.Newtown Square, PA: PMI.
12.
SchmidtS. R., & KiemeieM. J. (2002). Don't let TQM Drain you dry without any ROI. Retrieved December 10, 2002 from http://www.airacad.com/tqmroi.htm
13.
Software Engineering Institute (SEI). (1994). The capability maturity model: Guidelines for improving the software process.Reading, MA: Addison-Wesley.
14.
WidemanR. M. (1992). Project and program risk management, A guide to managing project risks and opportunities.The PMBOK Handbook Series, Volume No. 6. Upper Darby, PA: PMI.
