I read a lot that the performance of a site or a program is really important for the impression on the user and their decision to buy something/come back again later.

While this is logical, I wasn't able to find a study on this. I found a lot recommendations to work on the performance, and some companies published stories where they explain that this helped them to increase their profit - but I'm not able to find a normal study on this.

Such a study should give a detailed overview about what percentage of users become unhappy and don't visit the site again after which time spend or should at least proof that such a correlation exists.

  • By official do you mean done or sponsored by a government? by a reputable company or institution? who is considered reputable for this, a marketing company or a big name regardless of business orientation?
    – PatomaS
    Mar 31, 2014 at 5:57
  • It doesn't have to be done by a government, but someone "generally reputable". Any company would be fine, as long as they aren't simply telling their own story of success without any hard facts or are actually selling performance optimization tools Apr 3, 2014 at 17:22
  • Well, then you have many, The Nielsen article is a good guide, but it's times are based on an era where 20Kb was considered a limit for page size. Not to mention that as far as I remember, he hasn't done any test about it but used references from other authors. In any case, I'll check the books I have from him to refresh my memory.
    – PatomaS
    Apr 3, 2014 at 23:24

2 Answers 2


The closest I've seen is from the Nielsen Norman Group's website.

Relevant section:

  • 0.1 second is about the limit for having the user feel that the system is reacting instantaneously, meaning that no special feedback is necessary except to display the result.
  • 1.0 second is about the limit for the user's flow of thought to stay uninterrupted, even though the user will notice the delay. Normally, no special feedback is necessary during delays of more than 0.1 but less than 1.0 second, but the user does lose the feeling of operating directly on the data.
  • 10 seconds is about the limit for keeping the user's attention focused on the dialogue. For longer delays, users will want to perform other tasks while waiting for the computer to finish, so they should be given feedback indicating when the computer expects to be done. Feedback during the delay is especially important if the response time is likely to be highly variable, since users will then not know what to expect.

There are many studies like the ones I mention above on Internet, older Gomez studies, other CDN networks, Nielsen, etc.

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