This is my last attempt to explain this. I feel like my point of view about luck is being either misunderstood, or misrepresented. Either way, I'm going to clarify a few things.
In this thread, I was not referring to past seasons in regards to good draw, bad draw, or "unlucky vs lucky in the tournament in the tournament." That is a lot more subjective. We all have thoughts on it, but let's keep our focus on the kpom luck stat. I am specifically referring to the kpom luck stat. Nothing more. Nothing less.
Definition of kpom luck- basically it's discounting records in close games. Teams usually win and lose about half of their close games. Additionally, multiple studies have been done on the idea of winning close games being a skill (something predictive and reproducible) vs random fluctuations.
As far as I know, every single one has shown it's random fluctuations. For example, they would study teams in the first half of the year who won a disproportionate amount of close games. In the second half of the year, they tended to win almost exactly half of their future close games. The exact same thing happened with teams in the other end of the spectrum who were terrible in close games to start the season, would win about half of their future close games.
That is really strong evidence that "winning close games" isn't something that is a skill.
Additionally, if it's coaching, as sedz alluded to, you would expect to see the same teams, year in and year out rank near the top of the luck stat. But go back and look at past seasons. There is nothing to indicate the same teams are at the top of this metric year in and out.
Being lucky and being a really good team, aren't mutually exclusive. It's possible to be the best team in the country and also be the luckiest team.
One last thing to consider in regards to "clutchness." If I told you a player was performing way above their season averages between the 10 minute and 5 minute marks of the first half, I think most people's initial reaction is to say "well ok... But that's probably just a lot of statistical noise." No one writes an article saying, "He's a killer during that stretch. This player really knows how to turn it on between the 10 and 5 minute marks of the first half," because it sounds absolutely insane. Now apply the same reasoning to the end of the game. This is just another reason why I don't buy it.
Lastly, of course X is really good. They've also been very lucky this year too have the close game record they do. This doesn't mean they're going to lose their next close one, it just means they're not much, if any more likely than anyone else to win or lose a close game.
One more thing I'll touch on. When a 90% free throw shooter makes 2 FTs was he lucky? Stop and think. Yes. The expected value there is 1.8 points. We scored 2. We got 0.2 points above expectation there. That is fortunate. This doesn't mean making the FT is not a skill.
Same scenario. 50% guy makes both. We scored 1 point over expectation. We were lucky there too, but by a bigger amount.