Watching Marcus play D always puts a smile on my face. Grabbed a few clips from Houston. Sorry, I'm not much of a video editor.
http://youtu.be/hmjli8hakJYRegarding the article in the OP, those things must be so tough to measure. Smart gets a high ball screen on about half of his defensive possessions. He basically NEVER goes under the screen inside 25 feet. In that case, did he "keep his man in front"? I can tell you unequivocally that Smart isn't getting beat 46% of the time, but his "keep in front" is 54%. I question the value of that stat.
I also wonder how they count turnovers forced. Does taking charges count? If Smart deflects the ball and turner gets a steal, does that count? If Smart pressures a guy and he throws it out of bounds? If he swallows up an offensive player and forces a jump ball (or a timeout)?
The world of analytics isn't ready for Marcus Smart.