Apr
6
In order to get a feeling for why software projects overrun, answer me this question: how long will it take you to find all the pieces of a jigsaw and assemble them?
Instantly of course you want to know: how many pieces? where are they hidden? in software we can know roughly how many pieces, and have some ideas where many of them are hidden. But that’s hardly enough to give a realistic estimate when we don’t know what the picture is.
4 comments so far...
Estimates? You’re joking right?
And you want to know what the picture looks like? I’ve been working on a piece of software for a year now and the customer still has to decide what it’s going to do.
in that case you should go for the worst case scenario and assume that the jigsaw is blank.
or take the estimate provided by the crawly slimer on the team and multiply it by seventeen.
or think about the deadline for the 2012 olympics (now proudly referred to on lbc radio as ‘2013′because that’s when it might be ready by)and just shake your head and give up.
one constant remains true; you will never, ever be given enough resources to do the job comfortably on time
There’s a new drive for accuracy in time estimates at work. It’s accompanied by a metric that will affect our bonuses: IIRC, it was that 90% of our work needs to be done within a 10% deviation from out initial estimates.
Those who create design documents have to fill in an estimate for time to implement the design. I recently explained to my boss that we have had no training in estimation, and that programmer productivity typically varies by an order of magnitude.
I read up on COCOMO before talking to him, in order to have some ammunition. I discovered that, in the baselining study for COCOMO, once the vallues in the numerical models had been calculated from the data, COCOMO estimates were within 30% of the actual time 70% of the time. COCOMO works only on SLOC estimates or an FP count. If we move over to SLOC-based productivity metrics, I’ll know the company had lost its mind.
So even when you have a full spec, it’s hard to know how long things will take.
Are you looking at a government contract, perhaps with Capita?
leave a reply
You must be logged in to post a comment.