Project Management

Estimating Techniques

last edited by: Mark Hipwell on May 1, 2008 4:11 AM login/register to edit this page
Keywords: Estimating

Contents
1 Delphi
2 PERT Analysis

Delphi

Delphi (aka Wideband Delphi) is estimation by concensus. There is a good enough description in wikipedia: Wideband Delphi. However, this type of estimating is very interesting for the following reason. When people are presented with identical information, they almost always come to a slighlty different conclusion. The reason for this is the assumptions made by those people. If you run this type of estimating session in a closed environment (a meeting) then you have the opportunity to discover your experts / team members assumptions that are being made on the facts being described. This is gold dust to a project manager for identifying very early issues and risks.

PERT Analysis

PERT (Program, Evaluation, and Review Technique) analysis is a process by which you evaluate a probable outcome based on three scenarios: best-case, expected-case, and worst-case.)

The formula for PERT is: (Optimistic Estimate + (4 x Most Likely Estimate) + Most Pessamistic Estimate) / 6

For example:

The most likely estimate for building a wall is 10 days. If the weather is good though it could be done in 5 days. If the weather is bad though it could take 20 days.

5 + (4x10) + 20 / 6 = 10.8 days


last edited by: Mark Hipwell on May 1, 2008 4:11 AM login/register to edit this page


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