In a project I’m currently working on I use sticky headers (headers that stick to the top of the viewport while scrolling down) extensively. Because the user needs to be able to rapidly search through a lot of (faceted) content it’s important to have the filter controls available at all times, so using them make sense.
I couldn’t find any usability research data on the usage of sticky headers however, so I asked on ux.stackexchange.com. Although this hasn’t lead to any research data (yet) I did receive some good input and also shared the things I found while studying this design pattern.
If you have something to add please share it as a reply to my question on Stack Exchange.