This document discusses several software estimation techniques: Expert judgment involves talking to experienced people familiar with the project requirements. Comparative or analogous estimation extrapolates data from previous similar projects. Bottom-up estimation builds up estimates for individual tasks and aggregates them. Top-down estimation uses high-level estimates from past projects to determine overall effort. Algorithmic methods use mathematical models relating cost drivers to estimates. Being able to accurately estimate is important for project scheduling, budgeting, and resource management.

1. S O F T WA R E
E S T I M AT I O N T E C H N I Q U E S

2. Estimation of any project is HARD…!!!
WHY….???
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3. Because the only time you know precisely how long it takes to
complete a project is when it’s done. Up to the point of delivery,
teams use educated guesswork to predict the future. Bigger and
more complex a project is, the more expert opinion you need to
predict. Faulty estimates mean missing deadlines and breaking
budgets are the two of the main symptoms of project failure.
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4. Being a skilled estimator is a crucial part of setting schedules,
establishing budgets, managing resources and running a thriving
team and business. Knowing the size of the software to be
developed and an understanding of the complexity involved in
developing the same, the planner needs to produce an estimate of
the effort that would be involved.
There are a number of estimation methodologies to choose from
and here we’re going to look few tried-and-trusted ones that work
for most types of projects.
1. Expert judgment
2. Comparative or analogous estimation
3. Bottom-up
4. Top Down
5. Algorthmic Methods
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5. EXPERT JUDGMENT
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This is probably the most common way people get a project
estimation. Talk to the men and women with the best hands-
on experience and understanding of the project
requirements. Just make sure that everyone has the same
understanding of what needs to be delivered. And try to find
experts who will actually be working on the project.
The expert is able to factor in differences between the past
projects and the existing one, and the new techniques
involved in the new project.

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COMPARATIVE OR ANALOGOUS
ESTIMATION
If your current project is similar to past ones, take the data
from previous work and extrapolate it to provide your estimates
for the new job.
The new requirement may be compared to an old/completed
project to understand the similarities and differences.
Before proceeding, make sure to check whether those projects
were successful.

7. This method uses a detailed work breakdown structure, and is
best for projects you’re committed to. Each task is estimated
individually, and then those estimates are rolled up to give the
higher-level numbers. This process makes you think about
what’s required in order to take a step back to see if the big
picture still makes sense. You’ll receive more accurate results
this method, but it’s also a greater investment of time.
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BOTTOM UP

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TOP DOWN
Using a high-level work breakdown structure and data from
previous projects, you can add estimates for each project
work item to determine the overall effort and cost.

9. ALGORTHMIC TECHNIQUE
These models provide one or more mathematical algorithms,
which produce software cost estimate as a function of the
number of cost drivers.
COCOMO that we will be learning later is an example.
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10. THANK YOU
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