As far as the laws of mathematics refer to reality they are not certain; and as fast as they are certain, they do not refer to reality - Albert Einstein
All project work operates in the presence of uncertainty. Aleatory uncertainty - naturally occurring variances of the project elements. Epistemic uncertainty - a probabilistic event based uncertainty. These uncertainties create a risk to the success of all projects. To manage the risk encountered on projects, these uncertainties must be assessed, analyzed, modeled, addressed for their impact on the Probability of Project Success
To perform these activities, develop these models, make decisions based on the assessments and model, we must make an estimate - since uncertainty is ever-present.
To suggest that decisions can be made without estimating, is simply willfull ignorance of the principles of the mathematics of probabilistic and statistically (Stochastic processes) based systems and the management of these systems in the presence of uncertainty.
Some resources for managing in the Presence of Uncertainty
- Making Hard Decisions: An Introduction to Decision Analysis, Robert T. Clemen
- Risk Management in Software Development Projects, John McManus
- Managing Project Risk and Uncertainty: A Constructively Simple Approach to Decision Making, Chris Chapman and Stephen Ward
- Project Risk Management: Processes, Techniques and Insights, Chris Chapman and Stephan Ward
- Probability Methods for Cost Uncertainty Analysis: A Systems Engineering Perspective, Paul R. Garvey
- Practical Risk Assesment for Project Management, Stephan Grey
- Risk Happens!, Mike Clayton
- Technical Risk Management, Jack V. Michaels
- Making Multiple-Objective Decisions, Mansooreh Mollaghasem and Julie Per-Edwards
- Software Engineering Risk Management, Dale Walter Karolak
- Effective Opportunity Management for Projects: Exploiting Positive Risk, David Hillson
- Managing Risk: Methods for Software Systems Development, Elaine M. Hall
- Effective Management: Some Keys to Success, Edmund H. Conrow
These uncertainties - Aleatory and Epistemic - operate inside a System. The term system is often tossed around with no context, domain, or even a basis for understanding. Here's some of that basis
- Integrating Program Management and Systems Engineering: Methods, Tools, and Organizational Systems for Improving Performance, Eric Rebentisch
- Systems Management: Planning, Enterprise Identity, and Deployment, Jeffry O. Grady
- Decision Analysis for the Professional, Peter McNamee and John Celona
And of course, in the presence of these uncertainties, you'll need to estimate. Here's a set of resources for applying known to work principles, processes and practices for estimating in the presence of uncertainty.
So perhaps some reading will improve the understanding of how to estimate project work in the presence of uncertainty.
