Question: I've seen many statistics referenced along the lines of: 

> 
> Visitors decide where to stay on or leave a website within [7, 2, 11, 0.8 seconds] of seeing it.
> 
> 
> 

Typically the statistic is used when talking about the importance of appealing design, clear navigation, prominent display of relevant content, etc. Unfortunately the articles I've found aren't citing sources.

Where's the actual research to back this up? What seems to be the actual amount of time visitors are taking to determine if a site is relevant to them or not?

Answer: 
[This study](http://dl.acm.org/citation.cfm?doid=1835449.1835513) covers dwell times in general, as well as for various categories (entertainment, financial, etc.)

[Jakob Nielsen](http://www.useit.com/alertbox/page-abandonment-time.html) provides a good summary of the study, stressing the importance of surviving the first 10 seconds.
[This research by google](http://research.google.com/pubs/pub38315.html) says that even 17ms are long enough to rate the site.