Estimation of an IT project is not a pleasant exercise. However, it is part of project management.

Usually, the pain points are

  • Depending upon the role, we come up with own version of numbers.
  • Project Bidder, Project Governance intend to move the numbers down; Black sheep intends to move it north
  • Estimation implicitly mean a commitment to management
  • Estimation is made without clarity of requirements
  • Estimates are subject to stakeholders interests and personality

Some principles of estimation practice:-

  • Parkinson law – Work shall fill the time allocated for completion.
  • Today’s project is Tomorrow’s legacy
  • Quality/Reliability of Estimation cannot be better than the requirements
  • Poor congruence of stakeholders is a perfect recipe for disaster
  • Often one fails to understand the difference between –Effort and Duration in estimation.
  • Cost and Effort are associated with Work Breakdown structure while Duration associates to Critical Path.
    • Cost – Money Spent (Unit – Currency)
    • Effort – Work Time for a task (Unit – Person-Hours)
    • Duration – Calendar Time (Unit – Days)

Here’s one technique for estimation.

  • Discuss with responsible person of a task to identify – effort required when it’s all roses with no thorns in the path. Let’s call it – Optimistic (O) number.
  • Identify the effort when we, it’s all desert with no hope of oasis. Let’s call it – Pessimistic (P) number.
  • Pinch yourself, it’s a real world. Both the above cases are unlikely, Identify the effort. Let’s call it – Realistic (R) number.

The estimated number (E) is (O + 4R + P)/6 with Uncertainty(U) as P – O.

Always Report Estimated number E with Uncertainty U. Plan and be prepared for, Uncertainty U.

A yardstick for self-review of estimation maturity :

Review and update your Estimates E and Uncertainty U in iterations; Uncertainty U should decline.