What are best practice response times?

Hi all,
I currently produce a report for my senior management with the response times for all our web sites.
They have asked me to include a statement about what is best practice response times, so wondering if anyone can recommend a report or site from a respected authority.
Many thanks,

Here are several resources that are recognized as the authority in these metrics.

Google RAIL Model - https://developers.google.com/web/fundamentals/performance/rail

Jakob Nielsen (UX Guru)

Also check out an academic paper by Professor Fiona Fui-Hoon Nah - A study on tolerable waiting time: how long are Web users willing to wait?

http://sighci.org/uploads/published_papers/bit04/BIT_Nah.pdf (this paper is useful in that it compares various times from different studies. it also raises the issue of perceived performance (the user’s perception of time delay).

A few thoughts:

Consider multiple points in time rather than dwell on a single number. This is particularly important since a web page doesn’t display all at once, but in a series of steps.

How quickly should the page provide the first paint? (first visual cue that an element is rendered such as the top nav bar.)

When should the first meaningful content element begin to display?

When should all elements above the fold render (Speed Index)

At what point should the user be able to interact with the page after meaningful content has loaded. (Time to Interact)

Also, you may wish to consider expanding this. I had originally prepared a similar report but found it was important to tie in such things as:

how our site compares to the competion
what is the user satisfaction with the site? (Qualitiative metrics)

Hope this helps