> quite easily tell wheter the user finds what he wants or gets more and more stressed (faster and more undirected mouse movement) Could be just me but I don't

> quite easily tell wheter the user finds what he wants or gets more and more stressed (faster and more undirected mouse movement) Could be just me but I don't make frantic mouse movements when I'm stressed or can't find something. Also sometimes I just let the mouse drift around as I scroll or read that probably looks like undirected movement. My point being that I think these metrics have a lot of inherent noise. With mountains of data you hopefully see the averages shake out but my gut tells me you shouldn't put too much weight on the analysis of these kinds of metrics and they should be supported by other sources of user feedback with better SNR.