The Delphi technique was developed to gain expert consensus on estimates without group influence. It can be adapted for software cost estimation by having estimators provide anonymous estimates in rounds. A coordinator summarizes estimates between rounds and asks outliers to justify differences, iterating until consensus. A variation allows group discussion with the coordinator but maintains anonymous estimating to focus on variances. Additional information may be needed if consensus is not reached.

1. Delphi Cost Estimation
Shashwat Shriparv
dwivedishashwat@gmail.com
InfinitySoft

2. The Delphi technique was developed at
the RAND corporation in 1948 to gain expert
consensus without introducing the adverse
side effects of group meetings.

3. The Delphi technique can be adapted to software
cost estimation in the following manner:
•A coordinator provides each estimator with the System
Definition document and form for recording a cost
estimate.
•Estimators study the definition and complete their
estimates anonymously. They may ask questions of the
coordinator, but they do not discuss their estimates
with one another.

4. • The coordinator prepares and distributes a summary of
the estimators’ responses, and includes any unusual
rationales noted by the estimators.
• Estimators complete another estimate again
anonymously using the results from the previous
estimate. Estimators whose estimates differ sharply
from the group may be asked, to provide justification
for their estimates.

5. • The process is iterated for as many rounds as
required. No group discussion is allowed during the
entire process.
• The following approach is a variation on the standard
Delphi technique that increases communication while
preserving anonymity.

6. • The coordinator provides each estimator with a
system definition and an estimation form.
• The estimators study the definition, and the
coordinator calls a group meeting so that estimators
can discuss estimation issues with the coordinator and
one another.
• Estimators complete their estimates anonymously.

7. • The coordinator prepares a summary of the estimates
but does not record any rationales.
• The coordinator calls a group meeting to focus on
issues where the estimates vary widely.
• Estimators complete another estimate again
anonymously. The process is iterated as many rounds
as necessary.

8. • It is possible that several rounds of estimates will not
lead to a consensus estimate.
• In this case the coordinator must discuss the issues
involved with each estimator to determine the reasons
for the differences.
• The coordinator may have to gather additional
information and present it to the estimators in order to
resolve the differences.

9. Shashwat Shriparv
dwivedishashwat@gmail.com
InfinitySoft