There is an art (and a science) to numerical precision that seems lost in software, writing and conversation.
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@kevlin *) And even though the window is very wide, it generally isn't fake. In a lot of cases it's based on the actual historic performance of deliveries to your address or neighbourhood. If it's so wide, it usually means the delivery van covers a wide area and the actual route differs too much between days.
For my address, deliveries through PostNL are usually reported with an initial window of one or two hours, and updates (through their app) do get more specific and accurate.
@kevlin Another reason for it being wide, is if they can't plan/allocate ahead in which specific delivery van/delivery route it will be put for delivery, so they use estimates for the two (or more) most likely to be used.
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@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...
@mrotteveel @kevlin Indeed. That 09:50 figure being to the nearest 5 minutes is not, of itself, a problem. It will be calculated on the basis of the courier leaving the depot at time x, and having a number of journey segments of predictable length. So it's the earliest time that it might arrive. The 2 hour, or 5 hour, finger-in-the-air value? Yeah, it's adding that on and keeping the precision that's the problem
The expected arrival curve is nothing like a Bell curve
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@mrotteveel @kevlin Indeed. That 09:50 figure being to the nearest 5 minutes is not, of itself, a problem. It will be calculated on the basis of the courier leaving the depot at time x, and having a number of journey segments of predictable length. So it's the earliest time that it might arrive. The 2 hour, or 5 hour, finger-in-the-air value? Yeah, it's adding that on and keeping the precision that's the problem
The expected arrival curve is nothing like a Bell curve
@bellinghman @kevlin I have worked on transactional emails and push messages that communicate this type of information to users. Communicating time ranges like this, even with the "fake" precision is the easiest to understand for most people. From a business perspective, it also prevents unnecessary calls, and complaints, to customer service.
Being more vague and less specific, even it's mathematically more correct, is not "better", neither for the customer nor the company communicating it.
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I sometimes receive notifications that I can expect a delivery in a 2-hour window such as "between 12:07 and 14:07".
To quote to the minute shows a failure of understanding of what an approximate range is, as well traffic and logistics.
It's a 2-hour window of imprecision. Quoting to the minute shows a deep lack of understanding. Quoting to 5-minute intervals is just about acceptable. To 10- or 15-minute is more appropriate significance. But honestly, in this case, to the hour is just fine.
@kevlin
On the other hand, I hate when Timestamps are given relatively. I prefer unnessesary nanosecond precision over a vague "a few moments ago" any time. -
@kevlin you'll eat your words if they arrive at 09:50, spend five hours unloading your order, and leave at precisely 14:45.
@stevefenton That would be worthy of many social media posts, but for quite different reasons
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@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...
@mrotteveel The probability of arrival between 09:50 and 10:00 is comparable to that of 09:30 and 09:50, so perhaps they should round down. Then again, the probability of arrival between 09:30 and 09:50 is...
"You're delivery will arrive today (probably)" covers, I think, most eventualities.
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@kevlin *) And even though the window is very wide, it generally isn't fake. In a lot of cases it's based on the actual historic performance of deliveries to your address or neighbourhood. If it's so wide, it usually means the delivery van covers a wide area and the actual route differs too much between days.
For my address, deliveries through PostNL are usually reported with an initial window of one or two hours, and updates (through their app) do get more specific and accurate.
@mrotteveel I am not debating the size of the range, which is most likely informed and hedged based on history, I am debating its false precision.
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@mrotteveel @kevlin Indeed. That 09:50 figure being to the nearest 5 minutes is not, of itself, a problem. It will be calculated on the basis of the courier leaving the depot at time x, and having a number of journey segments of predictable length. So it's the earliest time that it might arrive. The 2 hour, or 5 hour, finger-in-the-air value? Yeah, it's adding that on and keeping the precision that's the problem
The expected arrival curve is nothing like a Bell curve
@bellinghman @mrotteveel Precisely
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@bellinghman @kevlin I have worked on transactional emails and push messages that communicate this type of information to users. Communicating time ranges like this, even with the "fake" precision is the easiest to understand for most people. From a business perspective, it also prevents unnecessary calls, and complaints, to customer service.
Being more vague and less specific, even it's mathematically more correct, is not "better", neither for the customer nor the company communicating it.
@mrotteveel @bellinghman My original posting covers that: that is why you communicate 10:00–15:00. Not only is the range more accurate, but you will also receive fewer complaints than 09:50–14:45.
(And yes, there is a small psychological trick in here that is worth knowing, and for that and other reasons it is better.)
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@kevlin
On the other hand, I hate when Timestamps are given relatively. I prefer unnessesary nanosecond precision over a vague "a few moments ago" any time.@xris That is slightly different and is a source of another line of rants of mine.
First of all, when you are dealing with past events, they are known and are not estimates. Reporting them with both precision and accuracy is desirable. Excessive precision is quirky, but not wrong; reporting an estimate of a future event with false precision is wrong.
OTOH reporting a past event with poor approximation invariably annoying and often wrong (both in its model and its implementation).
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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.
@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.
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