I’m not sure that giving the UI to the elderly is a truer test. Whatever difficulty they encounter, it’s just as likely that it could be because a previous expe

I’m not sure that giving the UI to the elderly is a truer test. Whatever difficulty they encounter, it’s just as likely that it could be because a previous experience with a different OS is shaping their expectations, or many other factors. It does seem that “time from 0 to successfully performing a novel task” is a good metric among many.