That doesn't quite seem the same. PDSA describes two phases - Plan/Do and Study/Adjust - resulting in two sets of changes to a system. They differ in the sense

That doesn't quite seem the same. PDSA describes two phases - Plan/Do and Study/Adjust - resulting in two sets of changes to a system. They differ in the sense of big vs little, forward looking vs. backward looking, hence four total. The methodology I described results in one set of changes to the system, with a very different distinction between measurement vs. analysis vs. planning (which in PDSA subsumes the other two in the first phase). I'd say that PDSA is very different from OODA, but that's why it shouldn't even be part of this discussion.