Wideband Delphi Technique George Ukkuru

Introduction Consensus based approach for estimation Developed in the 1940’s at Rand Corporation Team of experts prepare individual estimates.

Benefits Build a complete task list or work breakdown structure for major activities. Consensus approach helps eliminate bias in estimates. Eliminate hidden agendas or divergent objectives for inexperienced estimators or influential individuals. Does not require historical data to prepare the estimates. Straightforward and Repeatable process

Process Planning Kickoff Meeting Individual Estimation Estimation Meeting Assemble Tasks & Review Results

Planning Project Manager selects a team and a moderator Team consists of 3-7 team members Representation from all groups like development, testing etc Moderator to be familiar with the Delphi process Ideal to have the Project Manager as a part of estimation team Project Manager should not be the moderator as he will have stake in the outcome of the estimation

Kickoff Meeting Explain the Delphi process Read the vision and scope document or any supporting documents [Pre-requisites] Review the goals of the estimation session Brainstorm and note down the assumptions Generate the initial WBS Decide upon the unit for estimation

Individual Estimation Estimate the time required for each task Add any additional tasks to the WBS Add any missing assumptions

Estimation Meeting Moderator shares the estimates so that estimators can see the range of estimates Individual estimates are not shared Team members revises estimates based on group discussions Estimates are revised until no estimator wants to changes his/her estimates. Estimators agree that the estimates are acceptable.

Wide Band Delphi Example There estimators A,B and C are told to prepare the time required to prepare test scenarios for a project The initial estimations provided were A – 18 Hours B – 38 Hours C – 58 Hours The moderator then Calculates average estimate as 38 hours Returns this with their original estimates to the estimators

Wide Band Delphi Example The estimators then meet and discuss the estimates The initial estimations provided were A – 31 Hours B – 32 Hours C – 33 Hours The moderator then Calculates average estimate as 32 hours Asks the estimators if they agree with this as the estimate

Iterations in Estimations Round 2 XX Round 1 X X X

Assemble Tasks & Review Results Project Manager works with the team and collects the estimates from team members Compiles the final WBS, estimations and assumptions Reviews the final estimates with the estimation team

Ground Rules All estimation sessions must be performed individually with no group interaction Estimators must indicate factors affecting their estimates Estimators will ignore holidays, vacations and other similar factors Anonymity must be observed during the whole estimation process Estimation sessions should have a predefined time limit

Assumptions Assume that one person will perform all tasks Assume all tasks will be performed sequentially Assume that you can devote uninterrupted time to each task

About the Author George Ukkuru is working as a test manager UST Global Trivandrum. He is having more than 10 years of experience in the field of software testing. He holds various certifications like PMP,CAPM,CSTE etc. He can be reached at