In general the last author (in CS) is the one managing. I'm sure many a PhD student can tell you that their advisors, who are on every paper they write, have at

In general the last author (in CS) is the one managing. I'm sure many a PhD student can tell you that their advisors, who are on every paper they write, have at times provided little to no input (potentially providing negative value, at least with respect to the research topic at hand).