Re: Help with The Inevitable Question
- Hi Simon,
Many of my clients ask the same question. How estimate revamping an
You have to start from concrete facts:
1) your current application even it's not perfect works every day.
2) Your application is based on VB code, therefore this code is
the latest version of your application documentation.
3) You know all functions and methods, screens, data structure and
4) you may know how long a new feature took to be designed
developed and tested.
For my point of view your project is quite large so you may need a
proof of concept phase to estimate time and budget.
I think your gradual revamping is a good approach, upon these 4 basic
facts above you can estimate and budget for example section X which
will use that method, that class, this sort of data structure, this
database access. Use "playing cards" Scrum phase to estimate our team
velocity at day one.
Then refine your figures by using COCOMOII analysis, function points
estimate and add some contingency.
- I agree with whatever you are saying Roy.
But these are my observations/experience:
1. Most project managers have, heard of/Used (even if
poorly)/considered, Function points.
2. Very few have heard of Use case points.
3. Almost no one has heard of COCOMO (shame)
Someone somewhere (blast my memory) has made a very valid point about
estimations showing a graph which corresponds to one of a the
economics curve of law of diminishing marginal returns. This is a
curve of estimation accuracy.vs.effort expended on arriving at the
estimate. I think lot of organisation forget that!
--- In email@example.com, Roy Morien <roymorien@...>
>COCOMO-I was found to be deficient and in need of improvement) and
> Wonderful!! Apply mathematics and metrics (COCOMO-II - because
Function Points, which look great because of the emphasis on metrics
and measurement and historical 'facts' ... and THEN ADD SOME
CONTINGENCY ... which clearly indicates that all those metrics and
measurements and estimating methods don't work very well ... and ...
ummm ... what is the measure of 'some' in that 'add some contingency'
bit?I'm sorry to be appearing to ridicule your suggestion, H. but ...
well, yes, I am ridiculing your suggestion.
>and accurate statement of requirements, and a clear contractual
> My advice to Simon would be to first ask the clients to give a full
undertaking that if it is not stated in that specification, then it
will not be included in the developed system. The client must provide
that spec in sufficient detail for you to give an estimate of
sufficient correctness. They surely are not so unreasonable as to ask
you for accuracy without them also being accurate and correct and
>and so can be pointed to as the spec., then one may ask the question
> If the existing system can be seen as being exactly what they want,
Why on earth are they asking for a rewrite?
> An interesting fact that arose from my research (albeit areasonably restricted research activity to admit to the facts) into
software estimating. I researched amongst consulting firms and
contracting firms that represented well over 50% of the local
industry in my home city; not one of them used COCOMO of any vintage,
and not one of them used Function Point Analysis, and many of the
project managers had never heard of COCOMO or Function Points. Do I
come from the real boondocks of software projects?
>+0000Subject: [scrumdevelopment] Re: Help with The Inevitable Question
> Roy Morien
> To: scrumdevelopment@...: hmeftah@...: Mon, 1 Sep 2008 09:16:55
>revamping anexisting application.You have to start from concrete
> Hi Simon,Many of my clients ask the same question. How estimate
facts: 1) your current application even it's not perfect works every
day. 2) Your application is based on VB code, therefore this code
isthe latest version of your application documentation.3) You know
all functions and methods, screens, data structure andso on.4) you
may know how long a new feature took to be designeddeveloped and
tested.For my point of view your project is quite large so you may
need aproof of concept phase to estimate time and budget. I think
your gradual revamping is a good approach, upon these 4 basicfacts
above you can estimate and budget for example section X whichwill use
that method, that class, this sort of data structure, thisdatabase
access. Use "playing cards" Scrum phase to estimate our teamvelocity
at day one.Then refine your figures by using COCOMOII analysis,
function pointsestimate and add some contingency.Good luckH. Meftah
> Are you a friend magnet? Play now to win prizes for you and your