how to make great software estimates

HOW TO MAKE GREAT

SOFTWARE ESTIMATES

Greg Thomashttp://www.rambli.com

And it begins…How long does it take to build this widget?When will you be done?Do I know what am I doing?Where do I start?What did they ask for?Did I think this through?Have I missed something?Am I as fast as Jeff?

estimatingThese are all questions we ask ourselves when we, as developers, are presented with a new problem and asked to provide an estimate as to how long it will take AND when it will be ready.

START?Two questions with two answers where one does not necessarily answer the other.

WHERE DO WE

EXPERIENCEKNOWLEDGE UNDERSTANDING

How long it will takeIt starts with looking at your experience, knowledge and gaining a keen understanding of the problem.

It starts with 3 Core Tenants

Experience• Have I ever worked on this

component?• What language am I using?• Do I know this language?• Is this a hard problem?• Do I know the platform?• Do we have requirements?• Is this a high-priority?• When does it need to be done?

Experience starts the process of

asking yourself these

questions with each problem.

experienceThe person with the most practice in that particular area of development will always yield the most “near” accurate estimation as to what needs to be done and how.

Experience grows over time and increases with each success and failure.

You want to fail, to get better.

http://www.rambli.com/2015/10/factors-of-software-estimation-experience/

Ruby on Rails

ERPManufacturing

CRMDesign Patterns

MySQL

.NET

SharePoint

JavaPLACEHOLDER

Communications

PHP

Knowledge• Do you know what

language you are using?• Do you know the

underlying framework and architecture?

• Do you have Domain Knowledge to your field?

• Do you have expertise on the platform you are building on?

What do I know that I

can leverage in this

estimate?

KnowledgeThe culmination of everything we know applied to what we know about the problem and our experience.

http://www.rambli.com/2015/10/factors-of-software-estimation-your-knowledge/

UNDERSTAND“I didn’t understand the problem”

“I’m not 100% sure what to do here”

“It should just work”

“It didn’t do this last time”

All statements that are uttered after you have started coding, but failed to take the time to understand the problem you

are trying to solve.

Never start coding if you

do not understand

what you are trying to

code.

Understand the problem1) Know the end user and identify what they expect2) Learn the platform/architecture that you are building

on3) Write down your assumptions and vet them with your

users, peers and team.

There is no “should” when you Understand.

http://www.rambli.com/2015/10/factors-of-software-estimation-understand-the-problem/

When will We ship?

Not YETWe have only figured out how long it will take to accomplish our task

By Understanding the Problem, leveragingour Experience and applying our Knowledge we have created an estimatethat we feel can stand by.

But it is not shipping time!

JANUARY 2015SO When will it be ready?

Your ConfidenceIs the most important component to any estimate. How confident are you in your estimate? 75%? 80% ? 50%?

Whichever the percentage, that is your SLUSH, which is the amountof extra time you think you might need to accomplish this task.

http://www.rambli.com/2015/11/factors-of-software-estimation-slush/

And what should you not apply to

an estimate?

80mphSpeedDo not build “acceleration” or “in the zone” time to your estimates. You are only as fast as you are going now. Building in future “I’m gonna know it by then” numbers will only hurt you down the road.

No CopyingNEVER use someone else’s estimates as yours. You don’t have their experience, knowledge or understanding of the problem.

They are not yours, you are already behind if you take them as your own.

No GuessingGuessing is for the lazy – “I don’t know, say 200 hours” – this means nothing, this helps with nothing, it might as well have been 2 hours as the result will have been the same.

Good Estimates are composed of• Knowledge• Experience• Understanding the Problem• Condfident Slush

Bad Estimates• Apply Speed Factors• Copy other People• Guess

SO REMEMBER…

Good estimatesWill tell you how long and when you will deliverBad estimatesWill give you nothing

T h e e n dGreg Thomas

http://www.rambli.com