[toomim]

These researchers presume that their goal is to make users think that an operation is happening quickly, even if it is slow.

I thought the goal of a progress bar was to report reality, not manipulate users into thinking that your slow code is faster than it actually is.

Since when have dark patterns infiltrated academic HCI?

[WorldMaker]

My understanding (and I believe studies back this up) is that primary goal of a progress bar is to assure the user, in priority order: 1) the app has not crashed, 2) the app is busy doing something, 3) the app is busy doing something relevant to the user.

As a software developers things like % complete and estimated finish time are general far more useful (for debugging things like "what stage is taking too long", for instance), but those specific details are rather further down the list of priorities for most average users.

[toomim]

> My understanding (and I believe studies back this up) is that primary goal of a progress bar is to

Studies cannot "back up" a goal. The goal is defined by the designer, developer, or in this case, the researcher.

Users also want to know if the app is lying to them. Sometimes an app crashes but keeps showing a progress bar. Sometimes the app says that something will take less time than it does. The more that developers make progress bars that lie to them, the less that users can depend on progress bars to tell them the truth and make informed decisions about what to do with their lives. These computers are tools for them. You don't know better than your users.

[WorldMaker]

The point is that studies back up the requested priorities/interests of the users. You stopped at the word "goal" without reading the rest of the sentence. (ETA: Also from a pure syntax diagramming perspective, that parenthetical was tied to "my understanding" not "the goal".)

To make my early point more explicit: average users don't care about Progress Bars with exact percentages and to the second/millisecond estimate times. Users want Progress Indicators that tell them the app hasn't crashed, is busy, and is busy with something relevant.

Progress Bars in general are just a bad way to tell users the information they want, whether they "lie" or not. I agree that in the case of an unrecoverable crash, an application should no longer show a progress indicator. I agree that users dislike it when an app suggests something will take less time than it does, but I think "build better estimates" is a Halting Problem trap and I think the answer has to be "show fewer estimates" and "build intentionally worse estimates". "32.5%" and "ETA: 3:21:59" shows far more implied accuracy that any system can actually deliver on than "Fooing the bar" and "This may take a couple hours" do.

The point is that it isn't "lies" versus "Truth", but "uncertainties" versus "implied lies". The application is always likely uncertain how much time things will exactly take, that's the nature of software (and the vagaries of hardware/internet conditions/weather, plus the Halting Problem). Specific percentages and too accurate estimates lie in their own way that the tasks being taken are all fungible and exactly linear in time/space, that the possible error bars are in parts of a percent and seconds rather than tens of percent and minutes or hours. There's always going to be "implied lies" in a progress bar, the question in this article, this thread, and others is how do you present how much that "you don't yet know" to the user that doesn't give them the wrong impression?

Again, developers certainly care about the raw percentage of work done or the raw estimate down to the actual second, but those sorts of details do more harm to the user's value of the system than good. They sometimes think they want to know those raw scores, but those raw scores don't actually tell them what they want to know or what they need to know. It's not a "lie" to just not give those raw data to the user. It's sometimes more of a "lie" to give that raw data to the user and then frustrate the user that the last 1% is different from the first 1%, that the exact-to-the-second ETA was wrong by hours.

Progress Bars are one of the best Progress Indicators we have, but they aren't perfect and they confuse and frustrate users sometimes as much as they help.

[madsbuch]

Its a bit harder than that, I'd say. Imaging a progress bar showing progress of two consecutive operations eg. download and process. How should that progress bar be displayed? 50% for each? If download is 30 seconds and process is half an hour that is skewed.

I am having that exact problem in an application I am developing.

[thaumasiotes]

> Imaging a progress bar showing progress of two consecutive operations eg. download and process. How should that progress bar be displayed? 50% for each? If download is 30 seconds and process is half an hour that is skewed.

Display a progress bar for downloading, and then another one for processing. You can caption them, too.

[masswerk]

Downloading is an async operation of unknown duration, which is best represented by a spinner. Processing, on the other hand, should be deterministic. I'd say, have a spinner and a progress bar (dimmed, while the spinner is active, then switch to a dimmed, but filled spinner and an active progress bar.)

[atoav]

Imagine a train network operator who says: we cannot say how long a trip will take with 100% accuracy, therefore we are not going to tell you at all. And evwn more evil: on the trains they blind the windows and rob you of every clue that would tell you where you are and how fast you are going.

This would be pretty uncomfortable.

What train riders (and users) are interested in is how long a thing should take in principle as well as clues about whether they are on track. When reality differs from that it is ok, as long as the ETA is somewhat in the ballpark area of the actual time of arrival.

[masswerk]

On the other hand, time tables should provide actual data in linear time (not some "apparent time" – "You'll arrive in 'just fine' at your destination."). I don't know the extent of the download, but, if not not substantial, it should just add a small offset prior to the main operation. Otherwise, if you're downloading a huge database, you can draw estimates from progress and display a sub-progress of this first task. (There are APIs for this).

In the now gone days of usability, it was considered good practice to annotate the progress bar of a complex task by displaying textual information regarding the sub-task and the progress made. This could be considered here as well. (E.g., "Loading data, estimate: 3.4 secs.")

[ancarda]

Why use a spinner for downloading? Don't you know how many bytes you need to fetch and how many you have received so far?

wget has a progress bar, and it works perfectly fine.

EDIT: Though, if the server does not have a Content-Length header, you will get an indeterminate progress bar (a kind of spinner, I suppose) in web browsers, if that's the kind of thing you mean?

[_jal]

Downloads can occupy some fuzzy middle ground between unknown and deterministic.

The normal case is that bandwidth throughput can be estimated well enough to make humans happy. But a broken network throws that out the window and will do its best to find ways to make your progress bar behave weirdly.

I can't remember what it was, but there was a Mac app a very long time ago (System 7 era, in the 90s) - maybe a news reader? - that would eventually hide the progress bar and show a message about bad networking when that happened.

[masswerk]

There are browser APIs, as well. However, network performance may vary. Personally, I would add textual information, like an estimate of the time required.

[Fargren]

I'm pretty sure in most systems I use, processing time is not deterministic and it depends on what else the system is doing at the time and it's temperature, among other factor of which the progress bar won't be aware.

A progress bar will usually present the "expected" duration of several operations, [almost] none of which have a deterministic duration, or a deterministic ratio from one to the other. The best we can do is put heuristics in place to estimate how long the operations will take. We have some choices, such as estimating the total time or estimating each sub-operation separately. We can even use AI for the estimation, if we want to get fancy. But the problem is not tractable, and we'd rather given estimates where we can that just use spinners everywhere.

[elcomet]

And yet users prefer progress bars. You know the average duration of a data transfer and can show a progress bar even if it's not very accurate.

[reaperducer]

Wasn't this solved back in the days of floppy disk OS installation?

You have one progress bar showing progress for this floppy, and another showing progress for the entire operation.

[madsbuch]

That is indeed a solution :)

I was merely constructing a case for using fancy progress bar calculations. And conflating two non related operations into one might be one of those.

[WorldMaker]

I had great results using a circular progress bar instead of a linear one. If you allow the tail to "catch up" towards the head, but the head always moving forward (rotating clockwise) you can allow the progress bar to shrink without losing the illusion of forward progress. In the worst case where lots new tasks/sub-tasks are discovered on the fly, it acts directly as its own "spinner".

It's probably easier to visualize than describe, but I have longer descriptions on the thinking behind it on my blog/GitHub repo. Unfortunately, my demo site succumbed to JS CDN bit rot and I keep forgetting to update the demo to something more recent.

(ETA: Forgot the link: https://github.com/WorldMaker/compradprog Also thought I could point out that the idea mostly jives with the findings in the paper here.)

[atoav]

This is hard because predicting a duration for each process is hard. For some processes getting feedback that granular might be hard (for a download this is more or less easy, you get the moving window average downloadspeed and the total filesize and use simple arithmetic to get the duration). For other things this can be hard, e.g. if the peocess you use doesn't offer that kind of granular metrics.

[madsbuch]

Download speed is not too important when showing a progress bar (unless one wants to do somethings fancy). If you know total content length and how much you have downloaded you just calculate the fraction and update the progress bar according a couple of times a second.

[cjaybo]

That's fine if the progress bar is only indicating the progress of the download. As mentioned elsewhere in this thread, if the download operation is only one part of the overall process, things get quite a bit trickier -- what percentage of the overall progress do you assign to the download operation when external factors like network speed and system load come into play?

[marcosdumay]

Progres bars have several goals, but making yours users happy secure that they know how long they'll spend and not feeling like they waited too long is certainly one of them.

Why do you classify that as a dark pattern? It's not harming people in any way, but the opposite.

[reaperducer]

Why do you classify that as a dark pattern? It's not harming people in any way, but the opposite.

It's lying. Lying is inherently harmful. Just because a computer is doing it doesn't make it unethical. Especially since people trust computers to be precise and correct.

[marcosdumay]

It's only lying if your users are completely rational aliens that have linear perception of the passage of time.

By the way, people do really not expect progress bars to be correct. They may with they were, but not expect.

[nullserver]

Back in 90s the progress bar was so bad it was more entertainment.

5 minutes left, 4 minutes, 23 days, 1 minute, 4000 years left.

The last 1% Taking longer the first 99%

If you installed the same software repeatedly get an idea of how long each section of the bar would take.

Windows 3.1 I’m looking at you.

[cldellow]

Yeah, this used to be a real pain point.

Page 311 of the .NET Framework Design Guidelines has this quote from Chris Sells (then a program manager for .NET, I think):

> Please make progress reporting move forward, if for no other reason than my family makes fun of me when they see a progress report going backwards, as if it's my fault. Personally, I've implemented several progress percentage algorithms and while I often can't get the timing to be smooth through all stages of an operation, at least they always move forward. In fact, I think you'd have to work extra hard to make them move backwards.

[nullserver]

Oh I had forgotten about the going backwards ones! It was like the machine was personally taunting you.

[marcosdumay]

I've seen that on the Windows 10 file copy dialog just yesterday... but yeah, they existed back in the 90's too.

[toomim]

> It's not harming people in any way, but the opposite.

Please explain how lying to your users is good for them.