This document discusses effort estimation techniques for projects. It describes estimating as forming a judgment about the work required, and mentions common techniques like decomposition, expert judgment, analogy, and planning poker. It also covers risk identification and adding buffers to estimates and schedules to account for risks and uncertainties. Key points emphasized are estimating in hours or days, adding 25% to total costs for buffers, and that more estimation perspectives improve the accuracy and consensus of estimates.

1. Effort Estimation

2. What are we trying to answer?
How many hours of effort will this project
take?
How much will it cost to deliver this
project?
Approximately how long will it take?

3. Estimate
To form an approximate judgment or opinion regarding the worth,
amount, size, weight, etc., of;
calculate approximately:

4. Cone of Uncertainty

5. Estimation Techniques
Counting
expert judgment (individual and group)
Decomposition
Analogy
proxy estimation
planning poker
and wall estimation.

6. Wall estimation

7. Decomposition
Task decomposition refers to the whole-part
composition structure of a task model.
NGSOFT
• measure it in days
• Nothing gets done in less than half-a-day

8. Unit of Measure
Seconds, Days, Months, Years
Story points
What does AGILE/SCRUM say?
• Product backlog estimates are in points (fibonnachi)
• Sprint backlog estimates are in hours.
NGSOFT:
• We have not yet found customers commited enough to use
story points (except Telmap and MOD).

9. Risk and buffer
And
AND
AND?!?!?!?!?!

10. Risk
Risk is the probability of a significant negative impact on the
project.
Special causes contribute the risk to the project.
You manage special causes by
• Avoiding them
• Mitigating their effects
You should identify risk long before the task is ready to go

11. Buffer
Project Buffer: Create a buffer for the
project.
Feeding Buffers: Create a buffer for each
task that feeds into the critical chain.
Re-level the resources to account for
buffering changes to the plan

12. Calculating buffer
Rule-of-thumb method: one-half the length of the
chain the buffer terminates
Sum of Squares method: sum the squares of the
task lengths, then take the square root
NGSOFT
• Systems – 25% of total project cost (without management,
which is another 10%)

13. My XP
The more people estimate the task, the closer it is to real workdays
(estimation is better)
The more people estimate the task, the more consensus we have
over the estimation (team commitment is better).
The more people meet to plan the task – the more we learn about
what needs to be done (works BEST IF you have a QA member).
Don’t be afraid to requestion your reasoning (Sometimes we don’t
know/grasp what we are trying to estimate).

14. Now let’s go through the template
and make some changes to it