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mated along with the rest of the WBS tasks. The final result should be a complete task list,
including any additional tasks found, waiting time, and overhead tasks, with an estimate
attached to each task. Each team member should bring the results to the estimation session.
Estimation session
The estimation session starts with each estimator filling out an estimation form. Blank
estimation forms should be handed out to meeting participants, who fill in the tasks and
their initial estimates from their individual preparations. During the estimation session,
the team members will use these estimation forms to modify their estimates. After the
estimation session, they will serve as a record of each team member’s estimates for the
individual tasks, which the project manager uses when compiling the results. (Figure 3-2
shows an example of a typical filled-in estimation form.)
Before the team members fill in their forms, the moderator should lead a brief discussion
of any additional tasks that were discovered during the individual preparation phase. Each
task that the team agrees to add to the WBS should be added to the form; the team will
generate estimates for that task later in the meeting. If the team decides that the task
should not be included after all, the person who introduced it should make sure that the
effort he estimated for that task is taken into account.
At this point, the participants fill out the estimation forms. The estimation form contains
one row for each task being estimated. If there are more tasks than rows on the form,
more than one form can be used for the session. Each participant starts with a blank form
and writes the name of each task on consecutive rows. The estimate for that task should
be written into the “Estimate” box next to the task. The estimate boxes are then added up
and the total written into the “Total” box at the bottom of the Estimate column.
The moderator then leads the team through the estimation session:
1. The moderator collects all of the estimate forms. The estimates are tabulated on a
whiteboard by plotting the totals on a line (see Figure 3-3). The forms are returned to
the estimators.
Round 10
10 20 30 40 50 60 70 80
Effort estimates (not including overhead or calendar waiting time)
FIGURE 3-3. Initial estimates
2. Each estimator reads out clarifications and changes to the task list written on the
estimation form. Any new or changed tasks, discovered assumptions, or questions are
raised. Specific estimate times are not discussed.
ESTIMATION 45