Mildly interesting tweets by Jordan Sperber from HoopVision (data nerd) and retweeted by JC:

Jordan Sperber
@hoopvision68
Ball screen usage and efficiency by coach in this decade (min 100 games coached)
Top 5 usage: Keatts, D'Antoni, Byington, Christian, Duquette
Top 5 efficiency: Few, Otzelberger, Scott, Bennett, McDermott
LINK

Jordan Sperber
@hoopvision68
Same graph, but with the top 25 coaches this decade in adjusted offensive efficiency highlighted
LINK

Christian has very high usage, but average efficiency, Mojo shows up as having low efficiency and the best coaches, average usage and high efficiency.  IMO not very instructive to compare the two measures as there doesn't seem to be any significant correlation.