It seems "Everyone" knows they're highly disruptive for many situations but often times clients don't. Particularly in desktop applications this form of dialog is often misused, often disrupting a workflow.

I intellectually know all of the reasons to avoid them and some rare cases they may be warranted, and we have a great deal of anecdotal evidence and professional opinions in our questions.

I know there is published research on modal dialogs, but to my dismay few people reference this research when supporting or opposing the use of modals dialogs.

I know for example that distracting users while in a state of flow (such as writing an essay in Microsoft Word) can be easily destroyed by interruptions such as modal dialogs, having disastrous results on productivity.

In my particular case the issue is attention (working on the mistaken opinion that modal dialogs attract attention and comprehension) and productivity as the dialog disrupts workflow for a "confirmation".

What are the most convincing resources to give to a client who believes modal dialogs are not problematic?

I am particularly looking for scholarly articles, but high level explanations (which cite real data) may be applicable as well.

Wikipedia has a good list of "common knowledge" about and criticisms of modal windows, but even they mostly cite blog posts and a couple books.

  • 1
    Apologies - Please bring me up to speed, what is bad about modal dialogs? (For instance, the "Why do I need to provide my birthday?" link on the facebook login homepage?)
    – Anonymous
    Commented Oct 12, 2011 at 14:16
  • That's an unusual example (and not technically modal); modal dialogs are usually confirmation, pop-out boxes to edit a single/few input fields or warnings and thus disrupt what would normally be a smooth task flow. The facebook birthday window isn't modal (the rest of the page functions while it is up) and it is purely informational and brought up on request, not in (unwanted) interruption of a task.
    – Ben Brocka
    Commented Oct 12, 2011 at 14:35
  • I like this question eg Microsoft are world leaders in distracting, focus destroying modal windows that do not add anything to what I'm doing. I'd also love to see some research base too...
    – colmcq
    Commented Oct 12, 2011 at 14:51
  • 5
    I understand the pull for wanting to find research on every topic (after all, some clients will only believe you if you can hand them paper)--but--isn't the very definition/purpose of a modal specifically to be disruptive? It's meant to break the flow of what a person is doing to drive their entire focus to it. If that isn't the goal, then the modal is the wrong pattern to be using. Granted, the challenge is how does one communicate that fact effectively to the client (which is a good question I don't necessarily have an easy answer to).
    – DA01
    Commented Oct 12, 2011 at 15:01
  • 9
    Microsoft also has a nasty habit of making modals that aren't disruptive enough--such as when a background app pops up a modal that is also in the background so now the app is locked and you can't figure out why because the modal is behind another window.
    – DA01
    Commented Oct 12, 2011 at 15:02

5 Answers 5


Generally speaking, disruptions and distractions negatively affect human performance, a common finding in cognitive psychology. Many studies have shown that distraction greatly increases task time on a wide variety of tasks.

There also exist many Quantitative studies showing task performance is negatively affected by distractions (note these figures are not specifically for modal dialog distractions):

We can all relate to the above distractions, but what is their quantitative effect on our performance?
- Forgetting the as-left conditions: 45%
- Forgetting to return to the original task: 25%
- Original task out of control during distraction: 17%
- Not knowing changes after returning to original task: 13%

How does this relate to modal dialogs? Users find dialog windows distracting. The linked University of Minnesota study found users rated dialog windows to be considerably more distracting than two other tested window types.

Dialog windows in particular show an extreme effect on task performance (emphasis mine):

Results show that when peripheral tasks interrupt the execution of primary tasks, users require from 3% to 27% more time to complete the tasks, commit twice the number of errors across tasks, experience from 31% to 106% more annoyance, and experience twice the increase in anxiety than when those same peripheral tasks are presented at the boundary between primary tasks.

Subjects unanimously rated the dialog window as the most distracting (intrusive) awareness technique.

Other research has specifically found that interruptions from modal dialogs greatly increase error rates in a simple form workflow exercise.

On average, errors were made 7.14% (SD = 8.06%), 17.26% (SD = 7.28%) and 25.89% (SD = 9.88%) of the time in the zero-, one- and two-interruption conditions respectively

In addition, research on video games have shown that Calm Messaging improves task performance (pdf download link). Emphasis mine:

Games have shown that reducing demands on the user’s attention can aid performance; through the use of sound, speech, transient text, and animation, games communicate in a calm manner that promotes a fluid, uninterrupted workflow.

Bottom line: Modal dialogs can double error rates, increase time to task completion, and are near-universally despised by users. Alternate means of notification are often available and should be utilized wherever possible and appropriate.

  • 8
    I added another link and quote because there wasn't enough blue and yellow yet.
    – Ben Brocka
    Commented Dec 14, 2011 at 20:18
  • At this point I feel like pointing a great big j'Accuse at the vendors of ETL tooling for committing many cardinal sins in this area. For some applications the correct user interface really is a scripting language ... Commented Dec 15, 2011 at 15:34
  • 2
    @ConcernedOfTunbridgeWells every financial software ever also has this problem. WARNING HOLY CRAP: Are you SURE you want to perform that action? Every damn time.
    – Ben Brocka
    Commented Dec 15, 2011 at 15:42
  • For anyone who doesn't know, I can't award a bounty on my own answer (nor did I intend to) so don't worry if my answer is top voted, it won't get the bounty. I will manually award the bounty to the non-me answer with the most help research cited.
    – Ben Brocka
    Commented Dec 22, 2011 at 16:45
  • 1
    @BenBrocka The University of Minnesota research is not online anymore. Do you have a different source or an extra source?
    – Kevin M.
    Commented Jul 26, 2019 at 7:23

I have found that some of the works by Mihaly Csikszentmihaly is a really good start. His understanding of flow is of critical importance. The point is that the flow of a task is critical, and dialogs - or anything else - that interrupts this flow is bad in terms of performance in completing this task. His classic book Flow is a good start.

Of course, if the most important thing is not the individuals performance in completing the task, then this is less relevant - there may be a higher priority of Not Corrupting the Corporate Database, and so interrupting the Flow state is a good thing.

So I think you need to make sure that you address the question of what is most important.

And when I have finished my PhD, you can refer to that. It might not be for a while yet, though :(

  • I recall a study mentioned in an HCI course that suggested if Flow is interrupted it can take ~30 minutes to get back into it. For the life of me I can't find the article though.
    – Ben Brocka
    Commented Dec 21, 2011 at 14:52
  • Actually, CSMH argues that you may never achieve it again, if you lose it on one task or process. It is a very tenuous thing. Helping people towards it, and achieving "micro-flow" does seem to make them perform better. Commented Dec 21, 2011 at 15:09
  • FLow isn't quite what I meant actually; it was just a productive workflow (I think).
    – Ben Brocka
    Commented Dec 21, 2011 at 15:53
  • There is also the advantage that if you quote Mihaly Csikszentmihaly, your users will never be able to quote his name back at you. @Ben - Flow does apply at a whole lot of levels, down to just being productive and focussed. Commented Dec 22, 2011 at 15:30
  • 2
    @SchroedingersCat Did you finish your PhD yet :) Is it possible to view your findings / research
    – Kevin M.
    Commented Jul 26, 2019 at 7:01

I would like to contribute by pointing to an extract of Apple's iOS UX guidelines:

People appreciate being able to accomplish a self-contained subtask in a modal view, because the context shift is clear and temporary.

  • In the case of a completely self-contained workflow they can be okay, but I'm not asking about that. There are indeed situations where a workflow is completely inside of a modal window, but I don't think that's relevant to the question of how modals disrupt current workflow when they interrupt it.
    – Ben Brocka
    Commented Dec 22, 2011 at 16:28
  • 3
    +1 well said. Newbie web developers and especially designers love to jump a bandwagon theme of the new school. Hating modals is one of them. There is a time and a place for this. Commented Feb 6, 2013 at 17:47

Possibly related is this study looking at location-updating effect of doorways on context-memory

Gabriel A. Radvansky, Ph.D., from the University of Notre Dame in Indiana, and colleagues examined whether the location-updating effect of walking through a doorway reflects the influence of the experienced context, in terms of the degree of immersion of an individual in a specific environment, or in terms of a shift in context.

Three experiments were conducted using different environments.

  • In the first, smaller displays were used to measure the degree of immersion on location-updating effects.
  • In the second experiment, immersion was maximized using an actual, and not a virtual, environment.
  • The third experiment examined whether the original encoding context was reinstated by returning to the original location where the objects were encoded

You can put numbers into an argument and over think it while the answer is very simple right in your face, literally as a modal dialog.

I go by a simple guidelines of using modal dialogs.

  • If the application or web app cannot continue without the user's decision, use a modal dialog.
  • If your application or web app has to have the user's decision immediately more than 5% of its interaction, rethink your application to support more "oops" user scenarios such as using trash and archiving as opposed to permanently deleting things that can never be recovered by a quick decision.
  • User initiated modal dialogs do not count, meaning think of them as shortcuts or sub pages as they serve a purpose to quickly modify a small chunk of data. However, if it can be done inline effectively, inline wins over dialog.
  • Use the checkbox "next time do not warn me about [blah blah]" if the modal could potentially annoy but must be told like Firefox does.

User studies are nice but its sometimes difficult to know what to look for in terms of the numbers. Asking someone do you like this or that isn't so useful on its own. It should be noted how people feel after they use your application or web app. Do they feel annoyed, happy at ease etc? What is your desired feeling? Try using the app yourself trying to actually use it for what it is trying to accomplish for the end user and take your head out of the implementation. Be the user. You will quickly see the annoyances. Try to eliminate them if you can by your design choices in your app. Numbers are good but common sense is way more valuable.

  • Can you give an example of the kind of situation you have in mind for the third bullet? Commented May 29, 2012 at 15:31
  • In the case where the UI doesn't warrant a full screen AND is outside the scope of the current view. For example you are on a social website and someone requests to join your group. You would see a little message indicator on the top of the website you click on, it brings down a list of messages, you click on the group request message and up pops a small dialog that shows the person's profile, their reason for wanting to be in the group and you ability to cancel, deny, approve. Commented Feb 5, 2013 at 21:56
  • Thanks. A small window dedicated to the task makes sense, but I don't see that it would be better modal than non-modal. Why prevent the user from using the rest of the app until he's handled the request? Commented Feb 6, 2013 at 16:51
  • In the case where the user specifically asks for it. If the context has nothing to do with the other parts of the website, why not focus them? It makes no sense to hate modals for the sake of hating them. @naoise-golden (see below) said this very succinctly. Commented Feb 6, 2013 at 17:44
  • Here's an example of a good use: kippt.com try clicking on the signup link. Commented Feb 6, 2013 at 18:14

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