My bad, Top of the stack is in regard to performance.Stack ranking is present in every company even though it is not said so.I thought it is a generic term for perfornance comparison. I seriously don't think the 4 hours per day study is relevant for my line of work or a typical Manager's work.I work on multiple work items a day in that only two or three requires high concentration like debugging or writing code and rest is simply time consuming like reviewing others work,meetings,writing documentations etc.That needs time