Using the wideband-Dephi technique for software estimation

General steps for software estimation

The estimation problem is defined and the participants are selected during planning. The kickoff meeting introduces the problem to the participants. Each participant then individually prepares his or her initial task lists and estimates. They bring these items to the estimation meeting, during which several cycles lead to a more comprehensive task list and a revised set of estimates. The moderator then consolidates the assorted information, and the team reviews the results. When some predetermined exit criteria are satisfied, the process is completed.

Practical case: activity sequence

What follows is a script for an activity of collaborative estimation using the Delphi technique. A proposed problem is provided as an application case, but other may be used instead.

Role assignment

• Select one or two participants to act as monitor team.

Step 1: Planning

• The monitor team assembles a problem specification with enough information for work breakdown.

Problem specification example: Warehouse management software portfolio.
The problem statement is contained in pages 19 to 37 of the following report available through the Web:
http://www.lrgl.uqam.ca/cosmic-ffp/casestudies/fetcke1999b.pdf

• The monitor team selects other two to four estimators, defining at least the following roles: developer, software manager, quality assurance staff, to reflect a diversity of perspectives.

Following the example, the following roles are assigned: a developer, two software managers and a member of the quality assurance staff.

Step 2: Kick-off meeting

• The monitor team arranges a meeting of about one hour, be it physical or through synchronous interaction means.
• During the meeting, the Delphi technique is explained to those who are unfamiliar with it, and the problem specification is distributed to all participants
• The objective of the meeting is to gain a shared understanding of the problem specification.

Following the example, a synchronous Yahoo messenger session is conducted. Some Web resources explaining the principles of the Delphi method are provided. A PDF file with the problem specification was distributed some days before the meeting, and a discussion is held to gain a shared understanding of the problem. The session history is recorded for eventual analysis.

Step 3: Individual preparation

• The monitor team provides a format to record estimates per task, departing from the breakdown provided in the problem specification.
• Participants work individually, recording all their assumptions, during a reasonable period.

Following the example, the participants work during two days in their initial assessments. The following Table template is given to them:

Task	Estimate (days of effort)	Comments
...	...	...
...	...	...
...	...	...
Total	...	...

Step 4: Estimation meeting

• The monitor team merges the lists of tasks, summarizes the comments and produces a graphical representation for the estimations, preserving the anonymity of the participants.
• A synchronous group meeting is arranged to discuss the results contained in the report of the monitor team

Following the example, the following kind of diagram can be used for the representation of the different estimates.

• Depending on the divergence of the estimations and the degree of consensus, the monitor team decides whether to go for another round of steps #3 and #4 or not.

Following the example, additional columns can be used to record the history of assessments for each participant:

Task	Estimate (initial)	Estimate (#2)	Estimate (#3)	...	Comments (last estimate)
...	...	...	...	...	...
...	...	...	...	...	...
Total	...	...	...	...	...

Step 5: Final assembling and review

• The monitor team elaborates a final synthesis of the work of the participants.