scott wrote:
> Usually you can break the task down into smaller ones and then each of 
> them down again, until some sensible limit.  You (as a team or company 
> or group of companies) should then be able to quite accurately estimate 
> how long each of those tasks is going to take, assuming you have done 
> anything similar before.  You then get all those nice "critical path" 
> diagrams using MS Project that show you where the bottlenecks are and 
> what's taking up all the time.

While true, it's also true that most times (IME at least) the boss doesn't 
want to wait that long. In particular, the boss doesn't want to spend the 
time it takes to describe out all the details to the point where you could 
give an accurate estimate before he has an estimate he can rely on.

If you look at (for example) function point analysis, it requires that you 
know every field of every table in the database, every column of every 
report, every input to every entry form, what the equation is to calculate 
any derived information, and a few other things like that. By the time 
you've figured out an entire business system to this degree of precision, 
you might as well just code the damn thing.

Which is not to say my bosses aren't foolish, but clearly "design it all and 
we'll tell you" doesn't work in most situations. Especially when the 
requirements change faster than you can code them.

> I remember reading somewhere that people are pretty accurate at 
> estimating how long it will take them to do things, it's just they 
> consistently over- or underestimate the time.  So as long as you (as a 
> project manager) have some record of the peron's previous work, you 
> should be able to get a good idea how long it will take just by asking 
> them and factoring out their internal time scale multiplier :-)

 From experience, this is true. But you have to track things pretty well. 
Joel Spolsky has (http://www.joelonsoftware.com/) has software that tracks 
it and then does a statistical analysis to give you confidence intervals.

-- 
   Darren New, San Diego CA, USA (PST)
   My fortune cookie said, "You will soon be
   unable to read this, even at arm's length."

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