The narrative goes like this: Duke center Mason Plumlee - who has been a historically bad free throw shooter in his career - suddenly flipped the switch as a senior and became efficient from the line. The reason was that he developed a new no-dribble routine at the line, which somehow allowed him to focus and make the freebies. Now, for whatever reason, he's no longer a good free throw shooter.
Unfortunately - for Mason Plumlee - this is the type of national narrative that arises from people trying to interpret a too-small sample size. He a) changed his routine, and b) was making shots, so 'a' is the cause of 'b'. But math doesn't work that way.
Stepping into the way back machine, Kevin Pelton showed that free throw shooting is more random than other measurable basketball skills. And Ken Pomeroy, using John Henson as an example, demonstrated that big increases for bad free throw shooters are exceptionally rare.
Here is a game-by-game breakdown of Plumlee's free throw shooting this year.
Games two through seven featured free throw rates well above his career average. And this is when the stories started to be published about how his new zen approach was the bee's knees. In the seven games since then, he's failed to convert 70% a single time. It took enough of those games to sink his overall average down to the point that people are now noticing that his zen approach has cracks.
Which is the real Mason Plumlee? It remains to be seen, but history is certainly not on his side.