What is the most efficiently run agency/department in the U.S. federal govt.?

I was curious about this question so I did a google search. Curiously NASA came up several times as the most efficiently (or one of the most efficiently) run large department in the federal govt. I was surprised as it seems that historically they've had programs with massive cost overruns and delays similar to the Pentagon.


What do people say here and why?

 

Truly a trick question with no correct (honest) answer.

 

Getting serious replies (across 4 forums) has been difficult.

 

I've worked for the Federal government. Efficiency is never a metric. Metrics like fairness and inclusiveness (regarding how the citizenry is treated) makes efficiency irrelevant. Doesn't happen anywhere.