Why software projects take longer than you think: a statistical model (2019) • Hacker News Board

Re: Why software projects take longer than you think: a statistical model (2019)

#131

Post by crispyambulance » Wed, Mar 10, 2021, 12:50 PM UTC

kqr wrote: post #129

crispyambulance wrote: post #124

Earlier quoted context omitted.

> "here's when we think it'll be done, but sometimes shit happens and there'll be a delay" I agree that a statement like that would not be useful. What I am saying is that it's better to make a good effort at estimation but then keep the stake-holders informed about what is going on, about the challenges and the mid-project delays. Any "95%" confidence calculation is kinda dubious. It would only work if you have meti…

I think I can work out a 95 % estimation I am willing to stake money on even without the things you mention. It does take good management/culture, but if I don't even have that, I'm headed for the dumpster anyway and should go home and rethink the whole thing first. > What I am saying is that it's better to make a good effort at estimation But what does that estimation mean ? If we don't know after the fact whether t…

> I think I can work out a 95 % estimation I am willing to stake money on even without the things you mention.

I doubt it. It's dicey to do estimations even when everything is well understood, but if you lack detailed and accurate records of past work for very similar projects... the best you can do is pad like crazy, cross your fingers, meet the deadline and say your confidence interval calculation was "accurate."

Re: Why software projects take longer than you think: a statistical model (2019)

#132

Post by nednar » Thu, Mar 11, 2021, 8:19 PM UTC

triggercut wrote: post #88

nednar wrote: post #82

There are still people who develop software in traditional projects? As software can easily changed according to changing business needs, software is never really done. So, it's unnecessary to put it in a project. While you do a factory building project and decide a point at which you are done, you wouldn't do a car manufacturing project. Software development is more similar to building cars than to building factorie…

Don't get confused between Projects and Operations. What you are describing is actually akin to operational projects (albeit at the risk of bespoke designing and building each car). Projects in the traditional sense produce new assets with new value with new benefits meant to be operationalized. You need to segregate associated costs so that you can depreciate the value of the asset once it's operational. Usually the…

I see, so the financial side between projects and operations is also different.

When would you choose to do software as a project, coming from that perspective? Maybe the budget for operational things is more limited, and so you choose to do something as a project, although you know later on you also want to still change it?

Re: Why software projects take longer than you think: a statistical model (2019)

#133

Post by jbay808 » Fri, Mar 12, 2021, 8:09 PM UTC

crispyambulance wrote: post #131

kqr wrote: post #129

Earlier quoted context omitted.

I think I can work out a 95 % estimation I am willing to stake money on even without the things you mention. It does take good management/culture, but if I don't even have that, I'm headed for the dumpster anyway and should go home and rethink the whole thing first. > What I am saying is that it's better to make a good effort at estimation But what does that estimation mean ? If we don't know after the fact whether t…

> I think I can work out a 95 % estimation I am willing to stake money on even without the things you mention. I doubt it. It's dicey to do estimations even when everything is well understood, but if you lack detailed and accurate records of past work for very similar projects... the best you can do is pad like crazy, cross your fingers, meet the deadline and say your confidence interval calculation was "accurate."

If the lognormal distribution is correct, the 95% confidence interval is a bit over 5 times the developer's gut-feeling estimate. The 99% confidence interval is 10 times the developer's gut-feel estimate. We found a lot of data to back this up, but your mileage may vary.