How are carrier landings graded?
To paraphrase GySgt Foley from the movie An Officer and a Gentleman:   “My grandmother is an aspiring Naval Aviator!”
Anyway, I am a former LSO, and I pulled out my old LSO NATOPS manual to see if I could find book definitions of the criteria for each grade.  I can’t seem to find them, but they are as close to verbatim as I can remember as described in the answer here.
Worth noting, the grade is not always about the wire you catch.  In other words, OKs aren’t limited to the 3 wire, you can still get an OK for a 2 or 4 wire.  It all depends on how and why you got that particular wire.  For example, if you get low, just miss the ace and taxi into the 2, that would likely be a &quot;No-grade&quot;.  However, if you fly a sweet pass and dip just enough at the ramp to barely scoop the 2, that could still be an OK.  And anything in between is probably a &quot;Fair&quot;.
The same thing would apply to being way long and just barely grabbing the 4 to avoid a bolter, vs just barely missing the 3 after an otherwise solid pass.
Really though, the question is not really answerable in a useful manner to a lay person.  Judging any “sport” is subjective, and often the LSOs don’t even agree on a grade.  After watching literally thousands of landings over a few years and being mentored by senior LSOs you just develop an eye and a feel for what a good pass and bad pass look like.  (and there are always plenty of “tweeners” to argue over!)
It really boils down to subjectively assessing the duration and magnitude of the pilot's deviations from perfect, and the appropriateness and timeliness of corrections.  In other words. how much the airplane is &quot;moving around&quot; out there...