Micah Zenko at the Council on Foreign Relations rounds up answers from Daniel Byman (sometimes), Joshua Foust (maybe), Sarah Holewinski (probably not), Patrick Johnston (yes, if targeted selectively), and Pir Zubair Shah (probably, at least in Pakistan).

I have explored this question myself, as it pertained to Osama bin Laden (both before and after his death) and the removal of cartel leaders in Mexico. The latter question–whether leadership removals in Mexican drug-trafficking organizations leads to more or less violence–is the topic of one of my current working papers (somewhat outdated draft).