Post #1261261

2026-03-27 12:34 UTC

Received a message telling me to expect a delivery "between 09:50am and 2:45pm". To their credit, they avoided quoting the estimated range to the minute (or to the second!), but the implication of quoting such limits to a precision of 5 minutes is nonsense given that the window of uncertainty is 5 hours. When developing software systems, understand your domain and understand your users. Your users are human, so go with "between 10am and 3pm" to sound like you know what you're doing.

Replies (3)

@stevefenton@mastodon.social 2026-03-27 12:54

@kevlin you'll eat your words if they arrive at 09:50, spend five hours unloading your order, and leave at precisely 14:45.

Open ##1261281
@mrotteveel@mstdn.social 2026-03-27 13:34

@kevlin The problem with saying between 10 and 15, is that if they then arrive between 09:50 and 10:00, there will be people who'll complain that they arrived "too early", and if you then instead say between 09:00 and 15:00, then people will complain the window is too wide and "imprecise". The fake(*) precision is part of the message, that it's specific to your delivery and that you shouldn't bother contacting customer service to get a real time window. *: see next reply...

Open ##1261286
@Haskellelephant@bitbang.social 2026-03-27 18:06

@kevlin At least 2:45 must be "most likely". There is always a non-zero chance it doesn't arrive at all due to "acts of god". Then again, giving legal disclaimers by sms seems unwise... Sometimes though, the delivery is trying to uphold their part in a contract with some consequences involved. Sometimes, if you are not there, the package will be returned. Then precise times, if correct and if they matter, seem appropriate.

Open ##1261295