[snarf21]

Well said. My current rule based on experience is that estimates should only be hours/days/weeks/months/quarters/years with NO numbers. It is to give a sense of scale and effort so it could be prioritized and/or modified. If they want exact dates, then it is like you said, several days/weeks to go get an accurate date. I only wish that the sales team had to commit to closing dates the same way software teams do.

[mtippett]

That's actually a good hack. I tend to take a similar approach, but using approximate days in a fibonacci sequence.

Start at the high end, will it take... years: NO quarters: NO months: erm... NO. weeks: maybe days: Unlikely hours: Ha. No.

So you end up with a range (days?-weeks-months). That's too broad, what could go wrong to avoid making it months long project (well we could investigate X, Y, and watch for Z). What needs to go perfect for it to be days? (well we could... wait, days is unlikely).

Those discussions about the high and the low to get "reasonable" confidence are super important.

[snarf21]

Yeah, I always think about my structure as "some small number of h/d/w/m/q/y". I count 1 week the same as 3 weeks in terms of scale. ymmv

[brightball]

I’m a big fan of avoiding numbers in estimations. The moment a number is included, people start adding them together to create metrics that don’t show any useful information.

[cpeterso]

I really like your suggestion to use hours/days/weeks/etc without numbers. A similar suggestion I read for estimating (originally outside the context of software projects) was to use numbers with just one significant digit, so your estimate options would jump from 8, 9, 10, 20, 30, ...

The estimation mention I dislike the most is "t-shirt size". There is no clear relationship between S/M/L/XL. At least story points let compare two tasks. If you try to give t-shirt sizes points (e.g. "M = 2*S"), then you might as well skip the t-shirt abstraction and just use story points.

[novembermike]

The argument I've heard for T-shirt sizes is that if you go to numbers people try to add them together when that's just not how it works. I do agree that T-shirt sizes don't work that well though.

[cpeterso]

I see what you mean about trying to think abstractly instead of about numbers. But once you have t-shirt sizes for some tasks, what do you do with them? You can't compare them. You can't convert them to date forecasts. You can't use them for sprint capacity planning like you can with story points.