[121789]

Hours is insane. But ultimately time is money and opportunity cost. Software engineering can’t be the only engineering where you ask the engineers how much something will cost or how much time it will take and the answer is “it’s impossible to know”. Even very inaccurate estimates can be helpful for decision making if they are on the right order of magnitude

[zdragnar]

There's two things here that get overlooked.

First, people asking for estimates know they aren't going to get everything they want, and they are trying to prioritize which features to put on a roadmap based on the effort-to-business-value ratio. High impact with low effort wins over high impact high effort almost every time.

Second, there's a long tail of things that have to be coordinated in meat space as soon as possible after the software launches, but can take weeks or months to coordinate. Therefore, they need a reasonable date to pick- think ad spend, customer training, internal training, compliance paperwork etc.

"It is impossible to know" is only ever acceptable in pure science, and that is only for the outcome of the hypothesis, not the procedure of conducting the experiment.

[collingreen]

> "as soon as possible after the software launches"

This isn't true, just desired, and is one of the main roots of the conflict here. OF COURSE you would like to start selling in advance and then have billing start with customers the instant the "last" pr is merged. That isn't a realistic view of the software world though and pretending it is while everyone knows otherwise starts to feel like bad faith. Making software that works, then having time to deploy it, make changes from early feedback, and fix bugs is important. THEN all the other business functions should start the cant-take-back parts of their work that need to coordinate with the rest of the world. Trying to squeeze some extra days from the schedule is a business bet you can make but it would be nice if the people taking this risk were the ones who had to crunch or stay up all night or answer the page.

Trying to force complicated and creative work into a fake box just so you can make a gantt chart slightly narrower only works on people a couple times before they start to resent it. 10x that if management punishes someone when that fantasy gantt chart isn't accurate and 100x that if the one punished is the person who said "it's impossible to know" and then was forced into pretending to know instead of the person doing the forcing.

[skeeter2020]

My take: if they have not done the work to get to at least some degree of a spec, and they won't give you time to review and investigate, they get nothing more than a vague, relative t-shirt size.

[yetihehe]

I think software is one of those VERY rare things, where inaccurate estimates can actually be inaccurate by "orders of magnitude". After 20 years in the field, I still managed to use 2 months of time on a task that I estimated as 10 days.

[camel_gopher]

A rule that has suited me well is to take an estimate, double it, and increase by an order of magnitude for inexperienced developers. So a task the say would take two weeks ends up being 4 months. For experienced developers, halve the estimate and increase by an order of magnitude. So your 10 days estimate would be 5 weeks.

[bumby]

Something often overlooked in cost/schedule estimates is the nature of joint probability of actions slipping. Action A slips and causes action B to slip. I think software is tougher to estimate because the number of interfaces is often much higher, and sometimes more hidden, than in hardware.

[Scarblac]

That's a factor four or five ir so, so still less than an order of magnitude.

[njovin]

The next natural progression of this line of discussion between "the business" and engineering is for them to agree on a time range as an estimate. Engineering doesn't want to say it'll be done in 6 weeks, but they feel okay saying it will take between 4 and 20 weeks so this estimate is accepted.

You can guess what happens next, which is that around week 8 the business is getting pretty angry that their 4-week project is taking twice as much time as they thought, while the engineering team has encountered some really nasty surprises and is worried they'll have to push to 24 weeks.

[shiroiuma]

You're forgetting the part where the business expects the engineers to pull all-nighters so they can meet the deadline.

[skeeter2020]

it is still better to give a range though because 1. it explicitly states the degree of unknown and 2. no boss is going to accept 4-20 weeks, which means you start talking about how you can estimate with better accuracy and the work required to do so, which is a major goal of planning & estimation.

[lmm]

> Software engineering can’t be the only engineering where you ask the engineers how much something will cost or how much time it will take and the answer is “it’s impossible to know”.

Because it's not engineering at all. But even if it was, plenty of engineering projects are impossible to estimate - the ones that are doing something novel - and disliking that fact doesn't make it go away.

> Even very inaccurate estimates can be helpful for decision making if they are on the right order of magnitude

If what the business wants is an order-of-magnitude, they should ask for that; often (not always!) that's a lot easier.