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Aaron's Technology Musings

Who let this guy on the podium?

Agile Estimation?

If you can't write a design until you write some code, how do agilists (or agilistas - you decide where you sit) - do estimation?

I am really curious.  I have, and do, do the COCOMO thing, function points, and other techniques.  Occasionally, if I think the app is CRUD enough, I go down to "screens" based estimation... but more or less, I am interested in the details that drive you to think "40 hours" versus "8 hours".  And if you are doing agile and TDD, how you can ever come up with an estimate at all, at least before you write some tests which allow you to know... perhaps... what classes, and even more perhaps, what the FP of those classes will be, in your estimate.

I ask this not because I think estimation of effort up front is a good idea.  Largely, I think, it is a guess that we do given the information we have at the time, which, more often than not, is usually insufficient.  But every agilista is making a living, and if you are doing so, the people that, I dunno, pay you, are asking how long you think something will take, even before you have written the HOLY tests.

 Just curious... cause I am stumped.
 

Published Monday, August 04, 2008 10:42 PM by aarone

Comments

# re: Agile Estimation? @ Monday, August 04, 2008 9:59 PM

See Software Estimation by Steve McConnell.  Estimation is the same whether you are agile or waterfall.

Pat

# re: Agile Estimation? @ Monday, August 04, 2008 10:07 PM

So, before you write the tests, you do FP estimation?  Really?  Isn't that just carrying the design in your head rather than writing it down in classes before you write a single test?

Not to be facetious - but I am more curious about the idea that TDD causes design and how it interacts with being able to estimate design effort, much less dev effort.

aarone

# re: Agile Estimation? @ Tuesday, August 12, 2008 1:43 PM

Aaron, hey this is interesting blog. We use Agile, and that's the question everyone wants to know. Our methodology currently is a Scrum/XP blend of practices. For estimation, on the first full blown agile project we did, we started after a estimate of 3 months was made using standard methods. After 3 week long iterations, we said our estimate was off, it was going to take 10 months from the original date! Needless to say management was not happy. But guess what. That estimate was correct! I can't in a few paragraphs give you a full blown explanation of Agile estimation techiniques, but I'd recommen Agile Estimating and planning by Mike here's a link: Coh.http://www.amazon.com/gp/product/0131479415?ie=UTF8&tag=corporatecode-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=0131479415 Maybe we can discuss more next week!

Eric Landes

# re: Agile Estimation? @ Tuesday, August 12, 2008 4:20 PM

Looking forward to it Eric!  MADNUG is going to be a blast.

aarone

# I Promise To, Never Again, Estimate By... @ Monday, August 18, 2008 12:11 PM

* Screen Count Leads to the idea that Google.com can be replicated in 2 days if you can knock out 1 screen

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