Cgkdisc
.:Hall of Fame Member:.
Difficulty of a reachable par 3 hole for the skill level versus difficulty for a specific player in the field are separate issues. For example, a hole might be judged legitimately "fair" for a skill level based on scoring stats. However, the drive on this hole must bend sharply to the right making it particularly difficult for righties without a forehand.You didn't really answer the question. I agree that 50% is too low. Yes, a shot a player can execute less often is more difficult than one they can execute more often. Obviously there is also a threshold somewhere that is too high. Any take on the range within which shots are legitimately challenging yet not unfair or fluky?
Thus, this hole may not be particularly difficult for the field to shoot birdies and pars 90% of the time and at the same time be particularly difficult for specific players at that skill level to rarely get a birdie without an upshot throw-in let alone throw an ace. As a designer, I'm not sure it's a flaw requiring a shot shape or type of throw too difficult for some players who cannot or may never be able to throw that spin with enough power as long as they have the innate power to throw that distance with their dominant spin. The key for designers is to ideally balance this hole with another hole similarly difficult for players whose dominant spin is lefty hyzer/righty forehand.
With regard to percentages, we've had the discussion before that at least 2/3 of attempts should be successful to determine that hitting a gap is not fluky for players of a skill level. Less than 2/3 success starts falling closer to deciding whether a design element is too fluky, a specific player isn't at that skill level or it's possibly too difficult for a large pool of players at that skill level. In that case, the designer can look at the data and see whether the design seems "fair" for higher rated players, i.e. they have more success than lower rated players or the data shows that success is randomly achieved independent of a player's rating, i.e. fluky. Whether to retain that feature depends on whether the designer prefers the randomness as is or attempts to modify it to reward increasing skill levels.