Андрій Татчин "software project estimation: theory and reality"

Software Project

EstimationTheory and Reality

Andriy TatchynGeneral Manager at LaSoft

Table of content

• Introduction to estimation and estimation issues

• A theory of estimation

• Case Studies and real world examples

Failure Record

• Every year only United States spend nearly $250 billion on IT applications. Each year approximately 175, 000 projects are built. Many of those are fail.

• The Standish Group research shows a staggering 31.1% of projects that were cancelled before they ever got completed. Further results indicate 52.7% of projects will cost 189% of their original estimates.

• The cost of these failures and overruns are just the tip of the proverbial iceberg. The lost opportunity costs are not measurable, but could easily be in the trillions of dollars.

Source: The Standish Group Report 2014

“Bridges are normally built on-time, on- budget, and do not fall down. On the other hand, software never comes in on-time or on-budget. In addition, it always breaks down.”

Alfred Spector,

President of Transarc Corporation

Results

Source: Software Estimation: Demystifying the Black Art by Steve McConnell

Barry W. Boehm (born 1935) is an American software engineer, Distinguished Professor of Computer Science, Industrial and Systems Engineering; the TRW Professor of Software Engineering; and Founding Director of the Center for Systems and Software Engineering at the University of Southern California.

Source: Wikipedia

• http://csse.usc.edu/tools/COCOMOII.php

http://csse.usc.edu/tools/COCOMOII.php

CoComo II adjustment factors In many cases you will not be able to use Cocomo 2 because:

- The project size is not clear, and you have no idea how many lines of code (LOC/SLOC) the project will have.

- In most cases today we use several programming languages and frameworks to develop software. So Locs becoming less universal.

- In most cases, it is recommended to use your organizations' historical data and take into account described Cocomo 2 adjustment factors.


Hello my friend, how long will it take

to deliver the project?

This is how Business works and thinks:


Distinguish between estimates, targets, and

commitments.

This is how real world looks like:


There is no single point estimation

• While project in a progress it develops information that support more accurate estimation. We have better understanding of requirements, design and tasks become more detailed, plans become more clear.

• Estimates are dynamic and should be revised as more information becomes available or when requirements change.


The Cone of Uncertainty


Recognize a mismatch between a project’s business

target and a project’s estimate for what it is: valuable risk

information that the project might not be successful.

Case Studies

How I estimate software projects

• Collect as much information about the project as possible. You will need at least several meetings with a customer to understand his needs. Remember about the Cone of Uncertainty. Try to kill everything that is not clear.

• Good if mockups and UI design are ready, if not start initial Product Design Sprint creating User Stories, Mockups, and UI Design.

• I create a Work Breakdown Structure (WBS). During the initiation and planning it helps organize task structure; double-check if something is missing; and control project Scope on later project stages.

• Count first. We count Web pages, and functionality (User Stories) to understand the project size.

• When a team is already known invite everyone into the estimation exercise (works for small and medium projects). Team estimation is a very good team building exercise; it is easier to make a commitment when you do the estimation and it is proven that group estimations are more accurate.

• Budget expectations

• Schedule expectations

• Functional Requirements

• Non-functional requirements

Collect

• Mockups

• UI

• User Stories

• WBS

• Technology stack

• Database structure

• Application architecture

Design • Make sure that something you have designed is something that is expected by a customer.

Validate

• Functionality

• WBS items

• Web pages

• Proposal pages :)

Count • Implement a Law of large number.

• Involve Project Team.

• Multiply on your team index.

Estimate

Product Specification

Law of Large Number

(15-20 items)

Team index

Count

Define your customer needs, schedule and

budget early. Share your thoughts openly.

(Raboph Case Study)

Wristo Project, Historical data implementationNumber of pages: 6

Effort: 435 hours

Effort per page: 72,5 hours

Cost calculation= Number of pages x 72,5 x Diseconomy of Scale Index x Hourly Rate

Example of Bottom Up estimation

Remember about Indians, Chinese and the rest of the

world

(Manmeet story)

Thank You!

Questions and ideas are welcome!